For example, early cocoa butter pessaries had boric acid and tannic acid as essential ingredients.
Boric acid is currently used as an antiseptic, insecticide, flame retardant and to control the fission rate of uranium in nuclear power plants. Pretty powerful stuff.
Tannic acid is similarly a weak acid once used as a treatment for strychnine poisoning. Today it's used in wood stains and gives tea its distinctive taste and colour. Soaking one's feet in tannic acid (or strong tea) can help prevent blisters.
Still want to try cocoa butter pessaries?
To find out more, buy Casanova's Condoms - the lighter side of contraception by Laura Essendine. http://www.lulu.com/content/3340705
Please note: this post is for amusement only and should not be construed as contraceptive advice. Please see a registered health professional for this