Also agrochemical formulations such as Herbicides (some), insecticides, biocides (sanitizers), and spermicides (nonoxynol-9). Nonoxynol-9 is the primary chemical in spermicides to inhibit sperm motility. The most common active ingredient of spermicides is nonoxynol-9. Spermicides containing nonoxynol-9 are available in many forms, such as jelly (gel), films, and foams. The spermicides benzalkonium chloride and sodium cholate are used in some contraceptive sponges. Spermicides, vaginal foams, and douches are not effective for prevention of transmission. Spermicides are believed to increase the contraceptive effectiveness of condoms. Diaphragms and caps are often used in conjunction with spermicides. Barrier methods, coitus interruptus, and spermicides must be used at every act of intercourse. Spermicides are unscented, clear, unflavored, non-staining, and lubricative. Irritation may also occur due to spermicides that may be present. The least effective methods are spermicides and withdrawal by the male before ejaculation. Spermicides used alone are only about 91 percent effective. A misconception about spermicides existed in the 1980s and 1990s. Modern spermicides nonoxynol-9 and menfegol were developed from this line of research.