Patient in the context of Eye chart

Medicine is the science and practice of caring for patients, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness. Contemporary medicine applies biomedical sciences, biomedical research, genetics, and medical technology to diagnose, treat, and prevent injury and disease, typically through pharmaceuticals or surgery, but also through therapies as diverse as psychotherapy, external splints and traction, medical devices, biologics, and ionizing radiation, amongst others.

Medicine has been practiced since prehistoric times, and for most of this time it was an art (an area of creativity and skill), frequently having connections to the religious and philosophical beliefs of local culture. For example, a medicine man would apply herbs and say prayers for healing, or an ancient philosopher and physician would apply bloodletting according to the theories of humorism. In recent centuries, since the advent of modern science, most medicine has become a combination of art and science (both basic and applied, under the umbrella of medical science). For example, while stitching technique for sutures is an art learned through practice, knowledge of what happens at the cellular and molecular level in the tissues being stitched arises through science.

Evidence-based medicine (EBM), sometimes known within healthcare as evidence-based practice (EBP), is "the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients. It means integrating individual clinical expertise with the best available external clinical evidence from systematic research." The aim of EBM is to integrate the experience of the clinician, the values of the patient, and the best available scientific information to guide decision-making about clinical management. The term was originally used to describe an approach to teaching the practice of medicine and improving decisions by individual physicians about individual patients.

The EBM Pyramid is a tool that helps in visualizing the hierarchy of evidence in medicine, from least authoritative, like expert opinions, to most authoritative, like systematic reviews.

A medical specialty is a branch of medical practice that is focused on a defined group of patients, diseases, skills, or philosophy. Examples include those branches of medicine that deal exclusively with children (pediatrics), cancer (oncology), laboratory medicine (pathology), or primary care (family medicine). After completing medical school or other basic training, physicians or surgeons and other clinicians usually further their medical education in a specific specialty of medicine by completing a multiple-year residency to become a specialist.

A medical emergency is an acute injury or illness that poses an immediate risk to a person's life or long-term health, sometimes referred to as a situation risking "life or limb". These emergencies may require assistance from another, qualified person, as some of these emergencies, such as cardiovascular (heart), respiratory, and gastrointestinal cannot be dealt with by the victim themselves. Dependent on the severity of the emergency, and the quality of any treatment given, it may require the involvement of multiple levels of care, from first aiders through emergency medical technicians, paramedics, emergency physicians and anesthesiologists.

Any response to an emergency medical situation will depend strongly on the situation, the patient involved, and availability of resources to help them. It will also vary depending on whether the emergency occurs whilst in hospital under medical care, or outside medical care (for instance, in the street or alone at home).

Drug design, often referred to as rational drug design or simply rational design, is the inventive process of finding new medications based on the knowledge of a biological target. The drug is most commonly an organic small molecule that activates or inhibits the function of a biomolecule such as a protein, which in turn results in a therapeutic benefit to the patient. In the most basic sense, drug design involves the design of molecules that are complementary in shape and charge to the biomolecular target with which they interact and therefore will bind to it. Drug design frequently but not necessarily relies on computer modeling techniques. This type of modeling is sometimes referred to as computer-aided drug design. Finally, drug design that relies on the knowledge of the three-dimensional structure of the biomolecular target is known as structure-based drug design. In addition to small molecules, biopharmaceuticals including peptides and especially therapeutic antibodies are an increasingly important class of drugs and computational methods for improving the affinity, selectivity, and stability of these protein-based therapeutics have also been developed.

The medical history, case history, or anamnesis (from Greek: ἀνά, aná, "open", and μνήσις, mnesis, "memory") of a patient is a set of information the physicians collect over medical interviews. It involves the patient, and eventually people close to them, so to collect reliable/objective information for managing the medical diagnosis and proposing efficient medical treatments. The medically relevant complaints reported by the patient or others familiar with the patient are referred to as symptoms, in contrast with clinical signs, which are ascertained by direct examination on the part of medical personnel. Most health encounters will result in some form of history being taken. Medical histories vary in their depth and focus. For example, an ambulance paramedic would typically limit their history to important details, such as name, history of presenting complaint, allergies, etc. In contrast, a psychiatric history is frequently lengthy and in depth, as many details about the patient's life are relevant to formulating a management plan for a psychiatric illness.

The information obtained in this way, together with the physical examination, enables the physician and other health professionals to form a diagnosis and treatment plan. If a diagnosis cannot be made, a provisional diagnosis may be formulated, and other possibilities (the differential diagnoses) may be added, listed in order of likelihood by convention. The treatment plan may then include further investigations to clarify the diagnosis.

In a physical examination, medical examination, clinical examination, or medical checkup, a medical practitioner examines a patient for any possible medical signs or symptoms of a medical condition. It generally consists of a series of questions about the patient's medical history followed by an examination based on the reported symptoms. Together, the medical history and the physical examination help to determine a diagnosis and devise the treatment plan. These data then become part of the medical record.

In healthcare, a differential diagnosis (DDx) is a method of analysis that distinguishes a particular disease or condition from others that present with similar clinical features. Differential diagnostic procedures are used by clinicians to diagnose the specific disease in a patient, or, at least, to consider any imminently life-threatening conditions. Often, each possible disease is called a differential diagnosis (e.g., acute bronchitis could be a differential diagnosis in the evaluation of a cough, even if the final diagnosis is common cold).

More generally, a differential diagnostic procedure is a systematic diagnostic method used to identify the presence of a disease entity where multiple alternatives are possible. This method may employ algorithms, akin to the process of elimination, or at least a process of obtaining information that decreases the "probabilities" of candidate conditions to negligible levels, by using evidence such as symptoms, patient history, and medical knowledge to adjust epistemic confidences in the mind of the diagnostician (or, for computerized or computer-assisted diagnosis, the software of the system).

Personalized medicine, also referred to as precision medicine or systems medicine, is a medical model that separates people into different groups—with medical decisions, practices, interventions and/or products being tailored to the individual patient based on their predicted response or risk of disease. The terms personalized medicine, precision medicine, stratified medicine and P4 medicine are used interchangeably to describe this concept, though some authors and organizations differentiate between these expressions based on particular nuances. P4 is short for "predictive, preventive, personalized and participatory".

While the tailoring of treatment to patients dates back at least to the time of Hippocrates, the usage of the term has risen in recent years thanks to the development of new diagnostic and informatics approaches that provide an understanding of the molecular basis of disease, particularly genomics. This provides a clear biomarker on which to stratify related patients.

Geriatrics, or geriatric medicine, is a medical specialty focused on addressing the unique health needs of older adults. The term geriatrics originates from the Greek γέρων geron meaning "old man", and ιατρός iatros meaning "healer". It aims to promote health by preventing, diagnosing and treating disease in older adults. Older adults may be healthy, but they're more likely to have chronic health concerns and require more medical care. There is no defined age at which patients may be under the care of a geriatrician, or geriatric physician, a physician who specializes in the care of older people. Rather, this decision is guided by individual patient needs and the caregiving structures available to them. This care may benefit those who are managing multiple chronic conditions or experiencing significant age-related complications that threaten quality of daily life. Geriatric care may be indicated if caregiving responsibilities become increasingly stressful or medically complex for family and caregivers to manage independently.

There is a distinction between geriatrics and gerontology. Gerontology is the multidisciplinary study of the aging process, defined as the decline in organ function over time in the absence of injury, illness, environmental risks or behavioral risk factors. However, geriatrics is sometimes called medical gerontology.

A laboratory specimen is sometimes a biological specimen of a medical patient's tissue, fluids, or other samples used for laboratory analysis to assist in differential diagnosis or staging of a disease process. These specimens are often the most reliable method of diagnosis, depending on the ailment. For example, breast cancer biopsies, performed on laboratory specimens of breast tissue, yield just a 2% rate of incorrect diagnosis. Laboratory specimens may also include feces.

Akinetic mutism is a medical condition where patients tend neither to move (akinesia) nor speak (mutism). It is the most extreme disorder of diminished motivation. Akinetic mutism was first described in 1941 as a mental state where patients lack the ability to move or speak. However, their eyes may follow their observer or be diverted by sound. Patients lack most motor functions such as speech, facial expressions, and gestures, but demonstrate apparent alertness. They exhibit reduced activity and slowness, and can speak in whispered monosyllables. Patients often show visual fixation on their examiner, move their eyes in response to an auditory stimulus, or move after often repeated commands. Patients with akinetic mutism are not paralyzed, but lack the will to move. Many patients describe that as soon as they "will" or attempt a movement, a "counter-will" or "resistance" rises up to meet them.