A spermicide is a substance that kills sperm; it is placed into the vagina to prevent pregnancy. Spermicides do not protect against sexually transmitted infections or HIV (the virus that causes AIDS). Spermicides are most effective when they are used with a barrier method, such as a condom or diaphragm.

Spermicides are available as jelly, foam, cream, vaginal suppositories, and film. Most spermicides come with an applicator. The applicator is filled with spermicide and then inserted into a vagina right before intercourse.

A spermicide film or suppository is inserted deep into the vagina close to the cervix. Film or suppositories must be inserted at least 15 minutes before intercourse to allow the spermicide to dissolve and spread in the vagina.

One application of spermicide is used for each act of sexual intercourse.