What are they?
Spermicides come in several different forms, including creams, jellies, tablets, suppositories, foams and film. They contain a chemical called nonoxynol-9, which disables sperm on contact.

How do they work?
Spermicides are inserted into the vagina before sex, and contain ingredients that disable sperm. Once sperm are disabled, they are unable to fertilize a woman's egg. Spermicides are always used in combination with other forms of contraception (condom, cervical cap, diaphragm, etc.)

How effective are they in preventing pregnancy?
When used perfectly, spermicides are 82% effective in preventing pregnancy. However, with typical use they are only about 71% effective. The failure rate can be greatly reduced when spermicides are combined with a barrier method (condom, cervical cap, diaphragm, etc.)

What are the advantages?

What are the disadvantages?