Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns.. As per your complain white coating over the tongue seems to be due to yeast infection over the tongue known as Oral Thrush or Oral Candidiasis.. It can occur due to a number of causes like Dry mouth, poor immunity, other oral infections,intake of antibiotics and steroids, smoking etc.. You should consult an Oral Physician and get evaluated and a thorough clinical evaluation can help in diagnosis.. In case if thrush is diagnosed as the cause anti-fungal mouthwash like Nystatin mouthwash and clotrimazole lozenges can be advised for a 2 weeks.. Taking plenty of probiotics like Yoghurt and garlic will help.. In case if it still does not resolve oral antifungals like Fluconazole and Itraconazole can be given.. Drink plenty of water and maintain a good oral hygiene.. Chew sugar free chewing gum as it stimulate saliva flow.. Hope this information helps.. Thanks and regards. Dr. Honey Nandwani Arora.