You can purchase what are called spermicides in drug stores. They work by killing sperm and come in several forms – foam, gel, cream, film, suppository, or tablet. They are inserted or placed in the vagina no more than one hour before intercourse. If you use a film, suppository, or tablet wait at least 15 minutes before having intercourse so the spermicide can dissolve. Do not douche or rinse out your vagina for at least six to eight hours after intercourse. You will need to use more spermicide before each act of intercourse. You may protect yourself more against getting pregnant if you use a spermicide with a male condom, diaphragm, or cervical cap. There are spermicidal products made specifically for use with the diaphragm and cervical cap. Check the package to make sure you are buying what you want.
All spermicides have sperm-killing chemicals in them. Some spermicides also have an ingredient called nonoxynol-9 that may increase the risk of HIV infection when used frequently because it irritates the tissue in the vagina and anus which can cause the virus to enter the body more freely. Some women are sensitive to nonoxynol-9 and need to use spermicides without it. Spermicides alone are about 74% effective at preventing pregnancy. Medications for vaginal yeast infections may decrease effectiveness of spermicides.