Spermicidal condoms work by releasing spermicide during sex, killing any sperm that comes into contact with it. Spermicide is a chemical that destroys or immobilizes sperm, making it difficult for fertilization.
While the spermicide coating may offer additional protection against pregnancy, spermicide does not offer extra protection against STIs.
When buying spermicidal condoms, always read the label carefully and look for a brand such as Trojan that contains nonoxynol-9. This ingredient is the most common spermicidal agent.
Spermicidal condoms may cause irritation in some individuals who are sensitive to the spermicide.