Spermicides are a chemical method of contraception.
They can be used alone, or with a barrier contraceptive such as a diaphragm, cervical cap or condom. When spermicide comes in contact with sperm, it kills the sperm before they can enter the uterus and migrate to the fallopian tubes to fertilize the egg. Spermicides also kill some germs, such as gonorrhea. The most well known chemical spermicide is nonoxynol-9. Octoxynol is another.