27423
In China and Tibet , mercury use was thought to prolong life , heal fractures , and maintain generally good health , although it is now known that exposure to mercury vapor leads to serious adverse health effects .
 China, Tibet
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 China, Tibet