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. 

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.

Reference: crchealth.com, https://www.crchealth.com/types-of-therapy/what-is-drug-therapy/ , consulted on  july 5th,2019