中药
Calculus bovis, niu-huang (牛黃) or ox bezoars are dried gallstones of cattle used in Chinese herbology. In Asian countries, calculus bovis are sometimes harvested when steers ("Bos taurus domesticus" Gmelin) are slaughtered. Their gall bladders are taken out, the bile is filtered, and the stones are cleaned and dried. The bezoars may also be surgically removed by veterinarians when working cattle become ill. In western countries, they are usually discarded. Its equivalent in Vedic culture is Gorochana.