Pharmacology deals with study of drugs. Dental assistant requires having basic idea about various drugs used in dental practice. Knowledge about some basic drugs such as antibiotics, analgesics, antiseptics and disinfectants, astringents, dentifrices, obtundants, mouthwashes is expected from dental assistant. The chapters discuss these drugs, their mechanism of action, desirable properties and various formulations they are available for an effective use by the patient. Knowing these drugs by dental assistant is important for providing assistance to the clinician and for effective communication with various medical personnel visiting a clinical set up. It also aids in providing postoperative instructions and management of the patient.