A medical history is a collection of information about a patient which includes current medical data, the patient's past history of medical issues, the patient's family history, and relevant health information which can help a doctor or care provider tailor diagnosis and treatment to the patient. Taking a medical history is an important part of many doctor-patient interactions, and in medical schools, doctors learn about how to take medical histories accurately, respectfully, and quickly. People may refer to a medical history as an “anamnesis” in some regions of the world.

The medical history is designed to provide context as well as clues which could help a doctor arrive at a diagnosis. When the patient comes to the doctor, the doctor takes note of symptoms reported by the patient as well as clinical signs observed during the appointment. The doctor also asks a series of questions which are designed to shed light on the current situation, including when symptoms first appeared, what kind of medical issues the patient has had in the past, and what kind of family history the patient has.

Patient's charts form part of their medical history, and many charts include a quick reference at the top which takes note of major events in the patient's life which can be relevant. The doctor also asks questions about the patient's lifestyle, finding out how often the patient exercises, what the patient eats, and what the patient's family, work, and personal life are like. While some things may not seem immediately relevant, they can be valuable. For example, someone under a lot of stress at work can be at increased risk of medical conditions related to stress. Similarly, someone who is not sexually active would be unlikely to have a sexually transmitted infection, which can narrow down the diagnostic choices.

Many doctors offices and hospitals request that patients or their family members fill out a medical history form upon arrival. This form is used to quickly document major medical issues, ranging from a history of allergies to a description of the current problem bringing the patient to the doctor. The doctor can use the information to narrow down a diagnosis.

The medical history is a private document, and it will be closely protected to keep the patient safe. Some of the information could be damaging if released to someone who is not authorized to view it, and other information in a medical history could be about things that the patient wishes to keep private. Doctors are trained in how to preserve this information and how to ask open questions which will encourage a patient to answer honestly and accurately so that the medical history will be as complete as possible.