Rectal suppositories are used to administer a predetermined drug dosage to treat a variety of diseases and symptoms in a variety of patient populations. Certain medical conditions, such as digestive disorders, may be more effectively treated when the suppository is placed in a particular location of the patient's anal canal or rectum. A method and apparatus for inserting a suppository into an animal or human may include an applicator having a barrel and plunger. The barrel maintains a first gas flow path during insertion of a suppository and the plunger maintains a second gas flow path during withdrawal of the plunger. By maintaining the first and second gas flow paths, trapped air and suction effects on the suppository are minimized or eliminated. Furthermore, patients may immediately resume day-to-day activities. These benefits may encourage patients to maintain a course of treatment thereby potentially avoiding additional complications, hospitalization, and costs.