To insert a suppository, the hands should be thoroughly washed and gloves should be worn. Someone inserting a suppository should lie on his left side, and gently grasp the suppository between the thumb and second finger. The smaller end of the suppository should be placed on the rectal opening and then gently inserted into the rectum, making sure the suppository has passed the anal sphincter muscle. After insertion has been completed, the sphincter muscle should be tensed so that the suppository does not slip out. Effects should be noticeable after 15 minutes, or so.

Petroleum jelly should never be used to insert a suppository, however, water-based lubricants can be useful. Typically, suppositories are already lubricated, though. If pain or extreme pressure occurs as the result of inserting a suppository, it should be removed, and the health care provider notified. If improperly inserted, suppositories can damage delicate rectal tissue, exacerbate hemorrhoids, or cause rectal bleeding.

Suppositories are also commonly prescribed for use vaginally to treat infections or to provide lubrication for dry vaginal tissue. These are inserted in the same manner as tampons. In some women, vaginal suppositories can cause burning, inflammation, and itching. If the vaginal suppository is improperly inserted, pain and difficulty urinating can result. In fact, an improperly inserted vaginal suppository can cause a urinary tract infection, which will need to be evaluated by a health care professional.

Most rectal suppositories are used to treat constipation, and are typically glycerin based. Pediatricians often recommend glycerin suppositories for babies who are constipated. Glycerin suppositories are available over the counter at drug stores and other retail stores.

A person may need to insert a suppository when he is unable to take medications orally. This can occur when the individual is vomiting, and is unable to keep anything down. Medications such as acetaminophen, given to reduce pain and fever, and anti-nausea medications are available in suppository form.

A patient with hemorrhoids usually should insert a suppository. If need be, the health care provider can insert a suppository for the patient, or recommended an alternative method of treatment. For those who suffer from chronic diarrhea or other gastrointestinal problems, suppositories can worsen symptoms. Occasionally, a suppository will cause severe abdominal cramping, persistent diarrhea, and nausea. Although these side effects are generally rare, when they do occur, the health care provider should be made aware of them to rule out other, more concerning medical conditions.