Spermicide is a type of contraceptive that kills sperm or stops it from moving. You insert spermicide in the vagina before sex. The chemicals in the spermicide, such as nonoxynol-9, prevent sperm from entering the uterus. You can get spermicide over-the-counter. It's available in many forms, including cream, gel, foam, film, suppository and tablet.
Spermicide isn't a very effective birth control method when used alone. However, you can use spermicide with a barrier method — such as a condom, diaphragm or cervical cap — to improve its effectiveness with preventing pregnancy. Spermicide doesn't protect against sexually transmitted infections.