Sir/madam What causes (reasons) of tongue infection (totally upper layer became a white tongue) and how to take precautions to avoid the problem. So much facing pain. How to reduce this kind of problem totally. What kind of food we preferred? Which tablets and solution and tubes are better to use. Yearly twice it will happen, at present I use metrogyl, metronidazole gen a gel (ointment) three times in a day. Its usefully. What I do. Next.