<s>[INST] My 8 month old baby over the last two days has had her tongue turn black, starting in the back and moving forward.  She does not breast feed, has not recently taken medications.  She seems to be in no pain and the tongue feels the same temp as her body. [/INST] Hi.Welcome to HEALTHCARE MAGIC..I have gone through your query and can understand your concern..As per your complain black discolouration of tongue can be due to a condition known as Black Hairy tongue and can be due to a number of causes like lack of proper oral hygiene maintenance, overgrowth of bacteria or fungus, food debris accumulation, taking medication  etc..I would suggest you to maintain a good hygiene status of your infant like cleaning tongue with a tongue scraper, using a soft toothbrush to scrape your tongue, feeding with ample of fluids..It can take a few days to resolve and in case if it does not resolve consult a Pedodontist and get evaluated..Hope this information helps..Thanks and regards.Dr.Honey Nandwani Arora. </s>