Styptic weed, also known as horsetail or mare's tail, is a perennial herb with a hard, jointed stem. It has been used traditionally for its astringent properties, as it contains high levels of silica that can help to reduce bleeding and inflammation. Other synonyms for styptic weed include shavegrass, puzzlegrass, scouring rush, and snake grass. These names refer to the plant's rough texture, which resembles the abrasive surface of a file or a snake's skin. Styptic weed is a common ingredient in natural remedies for skin conditions such as acne, eczema, and psoriasis, as well as for digestive issues and urinary tract infections.