Catechu is an herb. The leaves, shoots, and wood are used to make medicine. The two types of catechu, black catechu and pale catechu, contain slightly different chemicals, but they are used for the same purposes and at the same dose.
Catechu is used for diarrhea, swelling of the nose and throat, dysentery, swelling of the colon (colitis), bleeding, indigestion, osteoarthritis, and cancer.
People apply catechu directly to the skin for skin diseases, hemorrhoids, and traumatic injuries; to stop bleeding; and for dressing wounds.
Catechu is included in mouthwashes and gargles used for gum disease (gingivitis), pain and swelling inside the mouth (stomatitis), sore throat, and mouth ulcers.
In foods and beverages, catechu is used as a flavoring agent.