Use this as a safe (contraceptive) rodenticide...

Tripterygium wilfordii
Tripterygium wilfordii, or lei gong teng, is a twining vine in the botanical family Celastraceae common to southern China. T. wilfordii and its botanical cousins T. hypoglaucum and T. regeli have been used in traditional Chinese medicine for over 2000 years, treating everything from fever and chills to edema and carbuncles. More recently it has been used to treat rheumatoid arthritis, chronic hepatitis, chronic nephritis, and several skin disorders. Some men given T. wilfordii by their doctors are not able to conceive children. T. wilfordii’s contraceptive effect has been anecdotally known in China for many years; the first published finding came in 1982. A derivative of T. wilfordii could be an effective pharmaceutical alternative to hormonal contraceptives.

Most of the current studies on Tripterygium extracts take place in China, under the auspices of the Jiangsu Family Health Institute and Beijing and Shanghai ’s Institute of Materia Medica. A group of researchers at Harbor-UCLA’s Medical Center has also investigated one of T. wilfordii’s derivatives, triptolide.

How does it work?
T. wilfordii has not been tested in men as a contraceptive. What we know about its contraceptive effects comes from studies on rodents and retrospective studies of men taking a Tripterygium preparation for some other medical reason. These studies show that low doses of various Tripterygium preparations produce significantly lowered sperm density, with the remaining sperm incapable of swimming effectively. One study suggests that, like nifedipine, T. wilfordii derivatives may act as calcium channel blockers (Bai 2002). Much current research is focused on establishing the mechanism by which the plant affects fertility and investigating potential toxicity and side effects.

How is it delivered?
In traditional Chinese medicine, men prescribed some form of Tripterygium would make a decoction by simmering peeled, dried roots of the plant for at least an hour. Depending on the malady being treated, a doctor would prescribe 15-25 grams of Tripterygium prepared in this way each day. Researchers have found that a decoction is an effective contraceptive at one-third of this dose, or 5-8 grams per day (Qian 1987).

Although the dried roots are commonly available in Chinese pharmacies around the world, Researchers do not expect that preparing a decoction everyday is a practical way to deliver a male contraceptive. They are investigating a number of different Tripterygium preparations as possible contraceptives. These preparations would most likely be delivered in the form of a tablet or pill.