Some sources:
1.food not digested completely because of weak digestion system.
2.Toxin, bacteria accumulated in the bowel causing gas.
3.Food poison.
You can find info from here:
http://book.sina.com.cn/nzt/changneigeming/index.shtml
1.food not digested completely because of weak digestion system.
2.Toxin, bacteria accumulated in the bowel causing gas.
3.Food poison.
You can find info from here:
http://book.sina.com.cn/nzt/changneigeming/index.shtml
选择“Disable on www.wenxuecity.com”
选择“don't run on pages on this domain”
