Contemporary medicine applies health science, biomedical research, and medical technology to diagnose and treat injury and disease, typically through medication, surgery, or some other form of therapy. The word medicine is derived from the Latin ars medicina, meaning the art of healing. 
Though medical technology and clinical expertise are pivotal to contemporary medicine, successful face-to-face relief of actual suffering continues to require the application of ordinary human feeling and compassion, known in English as bedside manner. 
See main article: History of medicine.
Prehistoric medicine incorporated plants (herbalism), animal parts and minerals. In many cases these materials were used ritually as magical substances by priests, shamans, or medicine men. Well-known spiritual systems include animism (the notion of inanimate objects having spirits), spiritualism (an appeal to gods or communion with ancestor spirits); shamanism (the vesting of an individual with mystic powers); and divination (magically obtaining the truth). The field of medical anthropology studies the various prehistoric medical systems and their interaction with society.
Early records on medicine have been discovered from early Ayurvedic medicine in the Indian subcontinent, ancient Egyptian medicine, traditional Chinese medicine, the Americas, and ancient Greek medicine. Early Greek doctor Hippocrates, who is also called the Father of Medicine,  and Galen laid a foundation for later developments in a rational approach to medicine. After the fall of Rome and the onset of the Dark Ages, Islamic physicians made major medical breakthroughs, supported by the translation of Hippocrates' and Galen's works into Arabic. Notable Islamic medical pioneers include polymath Avicenna, who is also called the Father of Modern Medicine,  Abulcasis, the father of surgery, Avenzoar, the father of experimental surgery, Ibn al-Nafis, the father of circulatory physiology, and Averroes. Rhazes, who is called the father of pediatrics, first disproved the Grecian theory of humorism, which nevertheless remained influential in Western medieval medicine. While major developments in medicine were occurring in the Islamic world during the medieval period, the Western world remained dependent upon the Greco-Roman theory of humorism, which led to questionable treatments such as bloodletting. Islamic medicine and medieval medicine collided during the crusades, with Islamic doctors receiving mixed impressions. As the medieval ages ended, important early figures in medicine emerged in Europe, including Gabriele Falloppio and William Harvey.
The major shift in medical thinking was the gradual rejection, especially during the Black Death in the 14th and 15th centuries, of what may be called the 'traditional authority' approach to science and medicine. This was the notion that because some prominent person in the past said something must be so, then that was the way it was, and anything one observed to the contrary was an anomaly (which was paralleled by a similar shift in European society in general - see Copernicus's rejection of Ptolemy's theories on astronomy). Physicians like Ibn al-Nafis and Vesalius led the way in improving upon or indeed rejecting the theories of great authorities from the past (such as Hippocrates, and Galen), many of whose theories were in time discredited.
Modern scientific biomedical research (where results are testable and reproducible) began to replace early Western traditions based on herbalism, the Greek "four humours" and other such pre-modern notions. The modern era really began with Robert Koch's discoveries around 1880 of the transmission of disease by bacteria, and then the discovery of antibiotics around 1900. The post-18th century modernity period brought more groundbreaking researchers from Europe. From Germany and Austrian doctors such as Rudolf Virchow, Wilhelm Conrad Röntgen, Karl Landsteiner, and Otto Loewi) made contributions. In the United Kingdom Alexander Fleming, Joseph Lister, Francis Crick, and Florence Nightingale are considered important. From New Zealand and Australia came Maurice Wilkins, Howard Floery, and Frank Macfarlane Burnet). In the United States William Williams Keen, Harvey Cushing, William Coley, James D. Watson, Italy (Salvador Luria), Switzerland (Alexandre Yersin), Japan (Kitasato Shibasaburo), and France (Jean-Martin Charcot, Claude Bernard, Paul Broca and others did significant work. Russian (Nikolai Korotkov also did significant work, as did Sir William Osler and Harvey Cushing.
As science and technology developed, medicine became more reliant upon medications. Pharmacology developed from herbalism and many drugs are still derived from plants (atropine, ephedrine, warfarin, aspirin, digoxin, vinca alkaloids, taxol, hyoscine, etc). The first of these was arsphenamine / Salvarsan discovered by Paul Ehrlich in 1908 after he observed that bacteria took up toxic dyes that human cells did not. Vaccines were discovered by Edward Jenner and Louis Pasteur. The first major class of antibiotics was the sulfa drugs, derived by French chemists originally from azo dyes. This has become increasingly sophisticated; modern biotechnology allows drugs targeted towards specific physiological processes to be developed, sometimes designed for compatibility with the body to reduce side-effects. Genomics and knowledge of human genetics is having some influence on medicine, as the causative genes of most monogenic genetic disorders have now been identified, and the development of techniques in molecular biology and genetics are influencing medical technology, practice and decision-making.
Evidence-based medicine is a contemporary movement to establish the most effective algorithms of practice (ways of doing things) through the use of systematic reviews and meta-analysis. The movement is facilitated by the modern global information science, which allows all evidence to be collected and analyzed according to standard protocols which are then disseminated to healthcare providers. One problem with this 'best practice' approach is that it could be seen to stifle novel approaches to treatment. The Cochrane Collaboration leads this movement. A 2001 review of 160 Cochrane systematic reviews revealed that, according to two readers, 21.3% of the reviews concluded insufficient evidence, 20% concluded evidence of no effect, and 22.5% concluded positive effect.
The practice of modern medicine combines both science as the evidence base and art in the application of this medical knowledge in combination with intuition and clinical judgment to determine the treatment plan for each individual patient.
Central to medicine is the patient-physician relationship established when a person with a health concern seeks a physician's help; the 'medical encounter'. Other health professionals similarly establish a relationship with a patient and may perform various interventions, e.g. nurses, radiographers, and therapists.
As part of the medical encounter, the healthcare provider needs to:
Contemporary medicine is in general conducted within health care systems. Legal, credentialing and financing frameworks are established by individual governments, augmented on occasion by international organizations. The characteristics of any given health care system have significant impact on the way medical care is provided.
Advanced industrial countries (with the exception of the United States)   and many developing countries provide medical services though a system of universal health care which aims to guarantee care for all through a single-payer health care system, or compulsory private or co-operative health insurance. This is intended to ensure that the entire population has access to medical care on the basis of need rather than ability to pay. Delivery may be via private medical practices or by state-owned hospitals and clinics, or by charities; most commonly by a combination of all three.
Most tribal societies, but also some communist countries (e.g. China) and the United States,  provide no guarantee of health care for the population as a whole. In such societies, health care is available to those that can afford to pay for it or have self insured it (either directly or as part of an employment contract) or who may be covered by care financed by the government or tribe directly.
Transparency of information is another factor defining a delivery system. Access to information on conditions, treatments, quality and pricing greatly affects the choice by patients / consumers and therefore the incentives of medical professionals. While the US health care system has come under fire for lack of openness  , new legislation may encourage greater openness. There is a perceived tension between the need for transparency on the one hand and such issues as patient confidentiality and the possible exploitation of information for commercial gain on the other.
Provision of medical care is classified into primary, secondary and tertiary care categories.
Primary care medical services are provided by physicians or other health professionals who have first contact with a patient seeking medical treatment or care. These occur in physician offices, clinics, nursing homes, schools, home visits and other places close to patients. About 90% of medical visits can be treated by the primary care provider. These include treatment of acute and chronic illnesses, preventive care and health education for all ages and both sexes.
Secondary care medical services are provided by medical specialists in their offices or clinics or at local community hospitals for a patient referred by a primary care provider who first diagnosed or treated the patient. Referrals are made for those patients who required the expertise or procedures performed by specialists. These include both ambulatory care and inpatient services, emergency rooms, intensive care medicine, surgery services, physical therapy, labor and delivery, endoscopy units, diagnostic laboratory and medical imaging services, hospice centers, etc. Some primary care providers may also take care of hospitalized patients and deliver babies in a secondary care setting.
Tertiary care medical services are provided by specialist hospitals or regional centers equipped with diagnostic and treatment facilities not generally available at local hospitals. These include trauma centers, burn treatment centers, advanced neonatology unit services, organ transplants, high-risk pregnancy, radiation oncology, etc.
Modern medical care also depends on information - still delivered in many health care settings on paper records, but increasingly nowadays by electronic means.
See main article: Doctor-patient relationship. The relationship between patient and carer, be they physician or nurse, is a pivotal aspect of medical practice.
The ideal taught in medical school sees the core aspect as the physician learning the patient's symptoms, concerns and values. The physician examines the patient, interprets the symptoms, and formulates a diagnosis to explain the symptoms and their cause to the patient and then proposes a treatment. The job of a physician is similar to a human biologist: that is, to know the human frame and situation in terms of normality. Once the physician knows what is normal and can measure the patient against those norms, he or she can then determine the particular departure from the normal and the degree of departure. This is called the diagnosis.
The four great corner stones of diagnostic medicine are anatomy (structure: what is there), physiology (how the structure/s work), pathology (what goes wrong with the anatomy and physiology) and psychology (mind and behavior). In addition, the physician should consider the patient in their 'well' context rather than simply as a walking medical condition. This means the socio-political context of the patient (family, work, stress, beliefs) should be assessed as it often offers vital clues to the patient's condition and further management.
A patient typically presents a set of complaints (the symptoms) to the physician, who then obtains further information about the patient's symptoms, previous state of health, living conditions, and so forth. The physician then makes a review of systems (ROS) or systems inquiry, which is a set of ordered questions about each major body system in order: general (such as weight loss), endocrine, cardio-respiratory, etc. Next comes the actual physical examination and often laboratory tests; the findings are recorded, leading to a list of possible diagnoses. These will be investigated in order of probability.
The next task is to enlist the patient's agreement to a management plan, which will include treatment as well as plans for follow-up. Importantly, during this process the healthcare provider educates the patient about the causes, progression, outcomes, and possible treatments of his ailments, as well as often providing advice for maintaining health. This teaching relationship is the basis of calling the physician doctor, which originally meant "teacher" in Latin. The patient-physician relationship is additionally complicated by the patient's suffering (patient derives from the Latin patior, "suffer") and limited ability to relieve it on his/her own. The physician's expertise comes from his knowledge of what is healthy and normal contrasted with knowledge and experience of other people who have suffered similar symptoms (unhealthy and abnormal), and the proven ability to relieve it with medicines (pharmacology) or other therapies about which the patient may initially have little knowledge.
The physician-patient relationship can be analyzed from the perspective of ethical concerns, in terms of how well the goals of non-maleficence, beneficence, autonomy, and justice are achieved. Many other values and ethical issues can be added to these. In different societies, periods, and cultures, different values may be assigned different priorities. For example, in the last 30 years medical care in the Western World has increasingly emphasized patient autonomy in decision making.
The relationship and process can also be analyzed in terms of social power relationships (e.g., by Michel Foucault), or economic transactions. Physicians have been accorded gradually higher status and respect over the last century, and they have been entrusted with control of access to prescription medicines as a public health measure. This represents a concentration of power and carries both advantages and disadvantages to particular kinds of patients with particular kinds of conditions. A further twist has occurred in the last 25 years as costs of medical care have risen, and a third party (an insurance company or government agency) now often insists upon a share of decision-making power for a variety of reasons, reducing freedom of choice of healthcare providers and patients in many ways.
The quality of the patient-physician relationship is important to both parties. The better the relationship in terms of mutual respect, knowledge, trust, shared values and perspectives about disease and life, and time available, the better will be the amount and quality of information about the patient's disease transferred in both directions, enhancing accuracy of diagnosis and increasing the patient's knowledge about the disease. Where such a relationship is poor the physician's ability to make a full assessment is compromised and the patient is more likely to distrust the diagnosis and proposed treatment. In these circumstances and also in cases where there is genuine divergence of medical opinions, a second opinion from another physician may be sought or the patient may choose to go to another doctor.
In some settings, e.g. the hospital ward, the patient-physician relationship is much more complex, and many other people are involved when somebody is ill: relatives, neighbors, rescue specialists, nurses, technical personnel, social workers and others.
In non-Western societies, the physician/patient relationship may be couched in different terms. The illness may be seen as a violation of the spiritual realm and the cure will be seen likewise as having to take place in the spiritual realm. Violation of some spiritual rule can result in illness; persons distant to the patient may have caused illness by manoeuvres in the spiritual realm, by cursing or causing another practitioner / shaman / healer to place the curse. Powerful faith in these factors can result in serious illness or cure. Spirits can be part of a culture's usual pantheon, ancestor spirits or arbitrary new spirit forces arising independently or as derived from an existing object in the real world: such as an animist spirit coming from a totem animal, mountain or other thing. As in the scientific West, the practitioner is assumed to have special knowledge or power, and is paid by the patient in some form.
A complete medical evaluation includes a medical history, a systems enquiry, a physical examination, appropriate laboratory or imaging studies, analysis of data and medical decision making to obtain diagnoses, and a treatment plan.
The components of the medical history are:
The physical examination is the examination of the patient looking for signs of disease ('Symptoms' are what the patient volunteers, 'Signs' are what the healthcare provider detects by examination). The healthcare provider uses the senses of sight, hearing, touch, and sometimes smell (taste has been made redundant by the availability of modern lab tests). Four chief methods are used: inspection, palpation (feel), percussion (tap to determine resonance characteristics), and auscultation (listen); smelling may be useful (e.g. infection, uremia, diabetic ketoacidosis). The clinical examination involves study of:
The medical decision-making (MDM) process involves analysis and synthesis of all the above data to come up with a list of possible diagnoses (the differential diagnoses), along with an idea of what needs to be done to obtain a definitive diagnosis that would explain the patient's problem.
This process is used by primary care providers as well as specialists. It may take only a few minutes if the problem is simple and straightforward. On the other hand, it may take weeks in a patient who has been hospitalized with bizarre symptoms or multi-system problems, with involvement by several specialists.
On subsequent visits, the process may be repeated in an abbreviated manner to obtain any new history, symptoms, physical findings, and lab or imaging results or specialist consultations.
Working together as an interdisciplinary team, many highly-trained health professionals besides medical practitioners are involved in the delivery of modern health care. Examples include: nurses, emergency medical technicians and paramedics, laboratory scientists, (pharmacy, pharmacists), (physiotherapy,physiotherapists), respiratory therapists, speech therapists, occupational therapists, radiographers, dietitians and bioengineers.
The scope and sciences underpinning human medicine overlap many other fields. Dentistry, while a separate discipline from medicine, is considered a medical field.
A patient admitted to hospital is usually under the care of a specific team based on their main presenting problem, e.g. the Cardiology team, who then may interact with other specialties, e.g. surgical, radiology, to help diagnose or treat the main problem or any subsequent complications / developments.
Physicians have many specializations and subspecializations into certain branches of medicine, which are listed below. There are variations from country to country regarding which specialties certain subspecialties are in.
The main branches of medicine used in Wikipedia are:
See main article: Medical specialty. In the broadest meaning of "medicine", there are many different specialties. However, within medical circles, there are two broad categories: "Medicine" and "Surgery." "Medicine" refers to the practice of non-operative medicine, and most subspecialties in this area require preliminary training in "Internal Medicine". "Surgery" refers to the practice of operative medicine, and most subspecialties in this area require preliminary training in "General Surgery." There are some specialties of medicine that do not fit into either of these categories, such as radiology, pathology, or anesthesia, and those are also discussed further below.
Surgical specialties employ operative treatment. In addition, surgeons must decide when an operation is necessary, and also treat many non-surgical issues, particularly in the surgical intensive care unit (SICU), where a variety of critical issues arise. Surgery has many subspecialties, e.g. general surgery,Transplant surgery, trauma surgery, cardiovascular surgery, neurosurgery, maxillofacial surgery, orthopedic surgery, otolaryngology, plastic surgery, oncologic surgery, vascular surgery, and pediatric surgery. In some centers, anesthesiology is part of the division of surgery (for logistical and planning purposes), although it is not a surgical discipline.
Surgical training in the U.S. requires a minimum of five years of residency after medical school. Sub-specialties of surgery often require seven or more years. In addition, fellowships can last an additional one to three years. Because post-residency fellowships can be competitive, many trainees devote two additional years to research. Thus in some cases surgical training will not finish until more than a decade after medical school. Furthermore, surgical training can be very difficult and time consuming. A surgical resident's average work week is approximately 75 hours. Some subspecialties of surgery, such as neurosurgery, require even longer hours, and utilize an extension to the 80 hour regulated work week, allowing up to 88 hours per week. Many surgical programs still exceed this work hour limit. Attempts to limit the amount of hours worked has been difficult because of the large volume of patients who require surgical care, the limited amount of resources (including a shortage of people willing to enter into surgery as a career) , the need to perform long operations and still provide care to all pre- and post-operative patients, and the need to provide constant coverage in the OR, ICU, and ER.
Medical training, as opposed to surgical training, requires three years of residency training after medical school. This can then be followed by a one to two year fellowship in the subspecialties listed above. In general, resident work hours in medicine are less than those in surgery, averaging about 60 hours per week in the USA.
Following are some selected fields of medical specialties that don't directly fit into any of the above mentioned groups.
Interdisciplinary sub-specialties of medicine are:
Medical education and training varies around the world. It typically involves entry level education at a university medical school, followed by a period of supervised practice or internship, and/or residency. This can be followed by postgraduate vocational training. A variety of teaching methods have been employed in medical education, still itself an focus of active research.
Many regulatory authorities require continuing medical education, since knowledge, techniques and medical technology continue to evolve at a rapid rate.
In most countries, it is a legal requirement for a medical doctor to be licensed or registered. In general, this entails a medical degree from a university and accreditation by a medical board or an equivalent national organization, which may ask the applicant to pass exams. This restricts the considerable legal authority of the medical profession to physicians that are trained and qualified by national standards. It is also intended as an assurance to patients and as a safeguard against charlatans that practice inadequate medicine for personal gain. While the laws generally require medical doctors to be trained in "evidence based", Western, or Hippocratic Medicine, they are not intended to discourage different paradigms of health.
Doctors who are negligent or intentionally harmful in their care of patients can face charges of medical malpractice and be subject to civil, criminal, or professional sanctions.
The Catholic social theorist Ivan Illich subjected contemporary western medicine to detailed attack in his Medical Nemesis, first published in 1975. He argued that the medicalization in recent decades of so many of life's vicissitudes - birth and death, for example - frequently caused more harm than good and rendered many people in effect lifelong patients. He marshalled a body of statistics to show what he considered the shocking extent of post-operative side-effects and drug-induced illness in advanced industrial society. He was the first to introduce to a wider public the notion of iatrogenic disease.  Others have since voiced similar views, but none so trenchantly, perhaps, as Illich. 
Through the course of the twentieth century, healthcare providers focused increasingly on the technology that was enabling them to make dramatic improvements in patients' health. The ensuing development of a more mechanistic, detached practice, with the perception of an attendant loss of patient-focused care, known as the medical model of health, led to criticisms that medicine was neglecting a holistic model. The inability of modern medicine to properly address some common complaints continues to prompt many people to seek support from alternative medicine. Although most alternative approaches lack scientific validation, some, notably acupuncture for some conditions and certain herbs, are backed by evidence.
Medical errors and overmedication are also the focus of complaints and negative coverage. Practitioners of human factors engineering believe that there is much that medicine may usefully gain by emulating concepts in aviation safety, where it is recognized that it is dangerous to place too much responsibility on one "superhuman" individual and expect him or her not to make errors. Reporting systems and checking mechanisms are becoming more common in identifying sources of error and improving practice. Clinical versus statistical, algorithmic diagnostic methods were famously examined in psychiatric practice in a 1954 book by Paul E. Meehl, which controversially found statistical methods superior. A 2000 meta-analysis comparing these methods in both psychology and medicine found that statistical or "mechanical" diagnostic methods were generally, although not always, superior.
Disparities in quality of care given are often an additional cause of controversy. For example, elderly mentally ill patients received poorer care during hospitalization in a 2008 study. Rural poor African-American men were used in a study of syphilis that denied them basic medical care.
. Medical Nemesis. Illich Ivan. Ivan Illich. 1974. 0714510963. 224760852. Calder & Boyars. London.
. Postman Neil. Neil Postman]]. Technopoly: The Surrender of Culture to Technology. Knopf. New York. 24694343. 1992.