Description
Vaginal spermicides come in three basic forms: creams, foams, and jellies. A spermicide is a chemical that kills sperm.

Effectiveness
Spermicides do not protect against STD's. Cream and jelly spermicides should never be used by themselves and are really only effective when combined with a conventional barrier method (i.e., condom, diaphragm, etc.). Foam spermicide can be used on its own, and if always used properly is around 95% effective. However, many people have difficulties using foam spermicide correctly every time they have sex. Some users do not completely fill the applicator ... others forget to shake the can. So, for a typical user, the effectiveness of foam spermicide is around 80% or less.

Directions
Spermicidal creams and jellies should be applied to the inside of a woman's cervical cap or diaphragm. The normal method for insertion of the barrier method is then followed. Normally, all spermicidal creams, foams, and jellies come with the applicator included. For applying spermicidal creams or jellies without a barrier method, screw the applicator onto the tube and fill it. Filling a foam applicator is a similar process. Insert the applicator into the vagina and push the plunger down. Remember, you are attempting to cover the cervix, so sperm have to travel through the spermicide to get to the uterus. Also, always consult a physician before choosing any birth control method.

Drawbacks
Vaginal spermicides tend to be very inconvenient. They must be applied no more than 20 minutes prior to intercourse. This requires a woman to always have to carry the spermicide and applicator with her whenever there is a possibility of vaginal intercourse. Another limitation of spermicides is that they have a chemical taste and can be a nuisance during oral sex. Some couples have found that spermicides provide too much lubrication, making intercourse less pleasurable. If an allergic reaction is experienced (a rash or itchiness is a sign of this), then the use of that spermicide should be discontinued.