Spermicides' function is to kill sperm. They are marketed to be more effective when used with condoms to prevent pregnancy. Nevertheless, there is no evidence to suggest that this is true.
- Spermicide and condoms used together are 98% effective as a means of contraception.
- Spermicide used alone without condoms is only 70-80% effective. This is the least effective method of contraception.
For some women, spermicides may actually cause vaginal irritation.
Condoms can prevent the transmission of sexually transmitted infections. For that, they should be used correctly at the beginning and throughout the act of intercourse.