Drug therapy, also called pharmacotherapy, is a general term for using medication to treat disease. Drugs interact with receptors or enzymes in cells to promote healthy functioning and reduce or cure illness. Medications are heavily researched and tested before being prescribed to patients, but may have unanticipated effects when combined with certain foods, herbal remedies or other drugs.

The method of administration for drug therapy varies depending on the patient and the condition being treated. Medications may be taken orally in pill, capsule or liquid form, or may be injected into the tissues or muscles.

As a function of eradicating disease, many drugs carry side effects which can be minor or at times severe. In most cases, side effects are temporary and do not last beyond the course of drug treatment