Puncture Vine

Tribulus terrestris (Devil's thorn, three-corner jack)
It turns out that this obnoxious weed, bane of feet and bicycle tires everywhere, has some beneficial properties. Its fruit (the part that inspires such complementary names for the plant) appears to stimulate the pituitary gland to secrete leutinizing hormone (LH) which in turn stimulates the gonads. Go figure.
Specifically, studies have indicated the ability of tribulus to increase a body's testosterone levels by as much as 30% in a week or less. The effects are apparently not immediate and must be accumulated. Testosterone controls agression and sex drive in both genders, so this increase is not insignificant to our studies here. The usual dosage is 250mg., taken two or three times a day.
This unlikely herb has actually been in use in the Far East for centuries, and has been the subject of study in Europe and America in the past few decades. It has been traditionally used as a liver tonic and is apparently a saponin-bearing plant (along with yucca, alfalfa and others), the practical meaning of which is that it binds colesterols in the digestive tract, preventing their absorption in the body and lessening the potential for heart disease, and also inhibits the viability and growth of cancer cells, making it anticarcenogenic especially in regards to colon cancer.