Triterpene saponins of marigold (Calendula officinalis; family compositae) were hydrolyzed and examined for their molluscicidal activity. It was found that 10.25 mg l(-1) of the partially hydrolyzed saponin was lethal to 100% of snails after 24 h, while 50 mg l(-1) of the intact saponin produced the same effect. Natural rubber, styrene-butadiene rubber, and starch were used as binding matrices for the bioactive natural products (C. officinalis) for releasing saponin in minute amounts over long periods of time. The rate of release of saponin varied according to the type of polymer matrix, the type of fillers, and the filler concentration. The rate of release extended to over 3 months when the physico-mechanical properties of styrene-butadiene rubber formulations were improved by the presence of black and white fillers.