During use of spermicides, either partner may feel burning, stinging, warmth, itching, or other irritation of the skin, sex organs, anus, or rectum. Using a weaker strength of vaginal spermicide or one with various ingredients may be necessary. If you are using benzalkonium chloride suppositories, it may help to wet them before they are inserted into the vagina. If any of these effects continue after you have changed products, you may have an allergy to these products or an infection and must contact a family doctor as soon as possible.