Tribulus is a plant that produces fruit covered with spines, also known as puncture vine. It is traditionally known as an aphrodisiac in various cultures and has chemicals that might increase levels of some hormones, although it doesnt appear to increase male hormones (testosterone) in humans. People use tribulus for sexual disorders, infertility, chest pain, enlarged prostate, and many other conditions, but there is no good scientific evidence to support most of these uses. Tribulus is also marketed as a dietary supplement to improve sexual function and for bodybuilding due to the belief that it acts like testosterone in the body. Tribulus has been used in traditional medicine for chest pain, heart problems, dizziness, skin and eye disorders, to expel kidney stones, and as a diuretic and tonic. Tribulus showed anticancer activities in lab studies, but it has not been tested in humans as a cancer treatment. Tribulus extract can relax blood vessels and may help to lower blood pressure. Tribulus is possibly safe for most people when taken at doses of 750-1500 mg daily for up to 90 days, but there isnt enough reliable information available to know if tribulus is safe to use for longer than 90 days or what the side effects might be. Side effects are usually mild and uncommon, but might include stomach pain, cramping, and diarrhea. Eating the spine-covered fruit of tribulus is likely unsafe and has been linked to serious lung problems. Tribulus may interact with certain medications, such as heart and blood pressure medicines, beta-blockers, digoxin, calcium channel blockers, diuretics, ACE inhibitors, nitrates, and diabetes medications.