Blisters on both sides of the tongue may be caused by viral infections, localized irritation, or dietary factors, and require medical attention to identify the cause of the problem and definitive treatment. 1. Viral infection: common in patients with colds and flu, due to viral attack on the upper respiratory tract, may also appear in the oral cavity, local manifestations of blistering on both sides of the tongue mucosa. 2. Local stimulation: non-disease factors, may be the tongue and teeth on both sides of the mechanical friction stimulation of the local mucosa, such as daily chewing, etc., repeated friction stimulation of the mucous membrane so that the tissue fluid leakage, the formation of blisters. Part of the population may be caused by the sharpness of the teeth on both sides. 3. Dietary factors: people who like to eat spicy and stimulating food, due to the body’s internal fire, will also be manifested as blisters on both sides of the tongue.