Hi there, Thanks for writing your query, Oral malodor is caused by number of reasons such as; Poor oral hygiene , improper brushing techniques which lead to accumulation of food debris and bacterial plaque and calculus deposits deep in the gum pockets and root surfaces of the teeth . bacterial plaque and calculus on the teeth gives fowl odor. Gingivitis and periodontitis is another condition which leads to mouth odor. Ulceration when infected with bacterial or viral invasion may lead to fowl smell. alcohol consumption also promotes plaque deposition and gives fowl odor. stomach reflux , GERD and other gastric problems may also lead to acidic mouth odor , you need to consult a physician to get the problem confirmed. i hope this helps , take care.