(6) Animal-based "herbs" are prone to substitution or adulteration, including Xiong Dan (bear bile / gall bladder) which looks very much like Niu Dan (bovine bile /gall bladder) when the gall bladder is dried, although Niu Dan is far less bitter in taste. Some are simply unavailable because they are banned in many countries. These include tiger parts, such as Hu Gu (tiger bone) which is substituted by bobcat bone, and Chuan San Jia (scales of the pangolin) which has no animal-based substitute. Niu Huang (bovine gallstone) is unavailable in many Western countries and Singapore because of its potential impact on pregnant women, although Niu Huang Pills with about 2% of Niu Huang are available in many Asian countries.