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 a first and second gas flow path, 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.