Tongue white moss thick bad breath may be due to increased oral bacterial reproduction caused by oral mucosal leukoplakia, and may be caused by oral candidiasis. 1. Physiological factors: the tongue is made up of food debris, shedding of oral mucosal epithelial cells and bacteria in the oral cavity, when there is no timely rinsing of the mouth leading to an increase in food debris in the oral cavity, or the human body’s immune system decline and other reasons leading to an increase in the propagation of oral bacteria, the symptoms of the tongue white moss thick, bad breath. 2. Oral mucosal leukoplakia: Oral mucosal leukoplakia is a kind of oral mucosal epithelial disease caused by tobacco, alcohol, betel nut, etc. It is a kind of pre-cancerous lesion, and patients with this virus can also have the symptoms of thick white tongue and bad breath. 3. Oral candidiasis: Oral candidiasis is a disease in which the oral mucosa is infected by Candida, which leads to inflammatory changes in the oral mucosa, and patients suffering from oral candidiasis may also have the symptoms of white tongue and bad breath. After eliminating the physiological factors, if the symptoms of white tongue and bad breath persist, you should consult a doctor to find out the cause and deal with it.