Astringents are substances that cause the contraction of body tissues, often used to reduce bleeding or inflammation. They work by tightening the skin and mucous membranes, which can help minimize the appearance of pores and control oil production. Common astringents include witch hazel, aloe vera, and calamine lotion, which are often found in skincare products. In addition to their cosmetic uses, astringents have medicinal properties. They can be applied to minor cuts and abrasions to promote healing and prevent infection. Some astringents, like tannins found in tea, can also be ingested to help with digestive issues, such as diarrhea.