Bottom Line: Tribulus has not been shown to treat or prevent cancer in humans.
Tribulus is an herb that grows in the subtropical regions of eastern and western Asia, southern Europe, and Africa. It is used in traditional medicine for chest pain, dizziness, skin and eye disorders, and to expel kidney stones. Tribulus is also marketed as a dietary supplement to improve sexual function and for body building due to the belief that it acts like testosterone in the body. However, this effect has not been confirmed. Studies done in lab and in animals show tribulus has medicinal effects against high blood pressure, diabetes, inflammation, infection, and cancer. However, there are no large scale studies conducted in humans.
Use of tribulus has been linked to adverse effects. Due to its potential hormonal activities, prostate cancer patients should avoid this herb until more is known about its safety.