puncture vine

Tribulus terrestris is a taprooted herbaceous plant that grows as a summer annual in temperate climates.

Growth pattern. The stems radiate from the crown to a diameter of about 10 cm (4 in) to over 1 m (3 ft 3 in), often branching. They are usually prostrate, forming flat patches, though they may grow more upwards in shade or among taller plants.

Leaves and stem. Stems branch from the crown and are densely hairy. Leaves are opposite and pinnately compound. Densely hairy leaflets are opposite and up to 3 mm (1⁄8 in) long.

Inflorescence. The flowers are 4–10 mm (3⁄16–3⁄8 in) wide, with five lemon-yellow petals, five sepals, and ten stamens. In Southern California, it blooms from April through October, where it is highly invasive in waste places and disturbed sites.

Fruit. After the flower blooms, a fruit develops that easily falls apart into five burs. The burs are hard and bear two to four sharp spines, 10 mm (3⁄8 in) long and 4–6 mm (3⁄16–1⁄4 in) broad point-to-point. These burs strikingly resemble goats' or bulls' heads, characteristics which give the bur its common names in some regions. The "horns" are sharp enough to puncture bicycle tires and other air-filled tires. They can also cause painful injury to bare feet and can injure the mouths of livestock grazing on the plant. Within each bur, seeds are stacked on top of each other, separated by a hard membrane. …

T. terrestris is currently widespread throughout the world from latitudes 35°S to 47°N. It is distributed across warm temperate and tropical regions of southern Europe, southern Asia, throughout Africa, New Zealand, and Australia. It is also present across southern North America and in Central and South America. Over the 20th century, it appeared in California and became distributed northward, eventually appearing in British Columbia, Canada where it is classified as a noxious weed. A network of fine rootlets arising from the taproot allow the plant to survive in arid conditions. It grows in almost any soil, but thrives in dry, loose, sandy soils, and even in sand or in deserts. It can prosper in heavier soils, especially if fertile or moist, and on compacted soils along roadsides.

Although its extract has been used as a dietary supplement since the 1980s in belief that it increases testosterone levels to aid body building or sexual enhancement in men, T. terrestris did not consistently affect testosterone levels in controlled studies and has not been proven to be safe. High-quality research on T. terrestris extract has not been conducted, and no reviews indicate that it has strength-enhancing properties or anabolic steroid effects as a bodybuilding supplement or sexual enhancement. The Australian Institute of Sport discourages athletes from using T. terrestris supplements, stating that there is no good evidence for their effectiveness or safety. A 2024 evidence map identified two low-quality clinical studies of oral T. terrestris tested for sexual symptoms of genitourinary syndrome of menopause in postmenopausal women, finding that the literature was too heterogeneous to draw conclusions.

The leaves and shoots are eaten in East Asia. The stems have been used as a thickener, added to diluted buttermilk to give it the appearance of undiluted buttermilk.

Dietary supplement. Although its extract has been used as a dietary supplement since the 1980s in belief that it increases testosterone levels to aid body building or sexual enhancement in men, T. terrestris did not consistently affect testosterone levels in controlled studies and has not been proven to be safe. High-quality research on T. terrestris extract has not been conducted, and no reviews indicate that it has strength-enhancing properties or anabolic steroid effects as a bodybuilding supplement or sexual enhancement. The Australian Institute of Sport discourages athletes from using T. terrestris supplements, stating that there is no good evidence for their effectiveness or safety. A 2024 evidence map identified two low-quality clinical studies of oral T. terrestris tested for sexual symptoms of genitourinary syndrome of menopause in postmenopausal women, finding that the literature was too heterogeneous to draw conclusions.

The plant is widely naturalized in the Americas and also in Australia south of its native range. In some states in the United States, it is considered a noxious weed and an invasive species. It is a "declared plant" in South Australia: its transportation and sale are prohibited, and landowners may be required to control it.

The Greek word, τρίβολος meaning 'water-chestnut', translated into Latin as tribulos. The Latin name tribulus originally meant the caltrop (a spiky weapon of similar shape), but in Classical times the word already meant this plant as well.