A medical doctor is a practitioner of the science of medicine who examines patients, diagnoses diseases, prescribes medications and treats diseases, disorders and injuries of the human body. Typical job activities include being a general practitioner who cares for all general complaints that do not require in-depth treatment, being a medical officer in hospitals, or a specialist in a specific field. The medical doctor questions the patient, takes a medical history and then performs a physical examination seeking the true cause of the complaint. Medication may then be prescribed, or the patient may be referred for further examination or treatment to a specialist. A general practitioner may perform small operations or assist surgeons with complicated operations.