A rotten tongue may be caused by a viral infection, most often seen in patients with herpes stomatitis, so antiviral medications, such as acyclovir, may be used. A rotten tongue may also be caused by an ulcer on the mucous membrane of the tongue. In this case, you can take multivitamin tablets and apply ulcer ointment, watermelon cream spray, furacilin-zinc oxide paste and lidocaine gel to the ulcer to promote healing and relieve pain. If the ulcer does not heal for a long time, it is necessary to seek medical attention. A rotten tongue may also be caused by fungal infection. Fungal stomatitis can cause white spots, white pseudomembranes and ulcers on the surface of the tongue, which can be treated by gargling with a weak alkaline solution, such as sodium bicarbonate solution, and by taking mycophenolate tablets for antifungal treatment.