The yellow tongue is also known as a yellow discoloration of tongue. Usually, it is a temporary and harmless problem. In most cases, yellow tongue is just an early sign of a disease that is known as black hairy tongue . In rare cases, yellow tongue may be a sign of jaundice (which is a yellowing of the eyes and skin), which sometimes indicates liver or gallbladder problems. Usually, the self – care is all what people need to treat this condition, unless it is related to another medical condition. Usually, the yellow tongue goes away on its own in time.
Yellow tongue symptoms
Here are the most common symptoms that are associated with the yellow tongue:
- An appearance of hair or fur on the tongue
- Bad breath
- Dry mouth
- There can be additional white patches, film, or coating on the tongue or mucous membranes
- Small, raised bumps on the tongue
- Burning sensation
- Sore throat
- A bad taste
If the yellow tongue is the only symptom, then you may do not need medical help. But if your tongue hurts, your skin or the whites of your eyes are also yellow, then ask for medical help. Also, if the yellow color does not go away after two weeks or you have other symptoms of jaundice, then ask for medical help.
Yellow tongue causes
The most common cause for yellow tongue is the buildup of skin cells and bacteria on your tongue . Often, this buildup is caused by the poor dental hygiene. It is noticed that jaundice is one of the most serious causes of yellow tongue. Also, there can be other causes for yellow tongue, such as
- Tobacco smoke: Tobacco smoke has chemicals which can make your tongue turn a yellow color. 
- Mouthwashes that contain oxidizing agents: If you use a mouthwash that contains menthol, witch hazel or peroxide, then you should be aware that it can turn your tongue yellow. 
- Medicines that contain bismuth: Those medicines which have bismuth can turn your tongue yellow and it can range from yellow to black. 
- Geographic tongue: This condition occurs when you are missing patches of papillae on your tongue. Doctors are not sure why this happens, but sometimes it runs in families. This condition gets its name because the missing patches make the surface of your tongue to look like a map. These patches are often red, but they can turn yellow too. In some cases, they can hurt.
- Dry mouth or mouth breathing: The lack of enough saliva in your mouth is known as dry mouth. Saliva washes bacteria out of the mouth and this can help to prevent tooth decay. Diseases like diabetes and Sjogren’s syndrome and the side effects of medicines, as well as chemotherapy and radiation can cause your mouth to dry out. Breathing in and out through your mouth while you sleep can also lead to dry mouth.
- Poor oral hygiene: If you are not brushing your teeth often and thoroughly, then the skin cells and bacteria can build up on the papillae of your tongue. Bacteria release pigments which can turn your tongue yellow. The tobacco, food and other substances can also get trapped on your tongue and turn it yellow. 
- Black hairy tongue: This is a harmless condition which happens when the little bumps called papillae that line the tip and sides of your tongue grow larger. Food, dirt, bacteria and other substances can collect on these bumps and turn them in different colors. Even though the black is the name of this disorder, your tongue can turn yellow or other colors before it turns black. 
Every single person can develop yellow tongue at any age, but there are few factors that are known to increase the risk of developing this condition. Here are the most common risk factors for yellow tongue:
- Disabling conditions
- Neurological conditions
- Autoimmune conditions
- Cancer 
- Alcohol use 
- Betel nut use
- Heavy consumption of coffee or black tea
- Tobacco use
- Poor oral hygiene
The yellow tongue usually does not cause any complications. But, the conditions which cause jaundice can lead to problems, like:
- Liver cancer
- Liver scarring
- Bleeding in your gastrointestinal tract
- Liver failure
- Enlargement of your spleen
- Swelling in your legs and belly
 Ye J, Cai X, Yang J, et al. Bacillus as a potential diagnostic marker for yellow tongue coating. Scientific Reports. 2016;6:32496.
 Brody B. The surprising thing that could be causing your bad breath. Johnson & Johnson. 2018. Retrieved from www.jnj.com/health-and-wellness/surprising-causes-of-bad-breath
 Tomooka K, Saito I, Furukawa S, et al. Yellow tongue coating is associated with diabetes mellitus among Japanese non-smoking men and women: The toon health study. Journal of Epidemiology. 2018;28(6):287–91. doi:10.2188/jea.JE20160169
 Cai H, Chen J, Panagodage Perera NK, et al. Effects of herbal mouthwashes on plaque and inflammation control for patients with gingivitis: A systematic review and meta-analysis of randomised controlled trials. Evidence-Based Complementary and Alternative Medicine. 2020.
 Brum JM, Gibb RD, Ramsey DL, et al. Systematic review and meta-analyses assessment of the clinical efficacy of bismuth subsalicylate for prevention and treatment of infectious diarrhea. Digestive Diseases and Sciences. 2020.