Spermicides are chemicals that kill sperm. They can be used alone or in combination with the condom, cervical cap or diaphragm. They also are toxic to some viruses and bacteria so they might lower the risk of some STD slightly.

They come in various forms including foams, jellies, creams, suppositories, tablets and films. The active ingredient is usually the same, nonoxynol-9.

Advantages:

• Available at most pharmacies, supermarkets and convenience stores.
• Relatively inexpensive.
• No prescription is necessary.
• Used in combination, like foam plus condom, up to 99% effective.
• Less partner cooperation necessary.
• As easy to use as putting in a tampon

Disadvantages:

• Must be placed in the vagina prior to sex.
• Can be messy or have an unpleasant taste or smell.
• Used alone can have a failure rate (chance pregnancy will occur) of up to 30%.
• Can cause a rash or burning sensation in the women or her partner.
• You shouldn't douche for at least 8 hours following intercourse.

All these products come with adequate literature describing their use.