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. IT IS USED IN PAAN(BETEL LEAVES). ALSO USED AS 1. Astringent 2. Cooling and digestive agents. 3. It is used in relaxed conditions of throat, mouth and gums. 4. It is also used in diarrhoea and in preparation of lozenges. Alos useful in mehandi.