Clear vesicles under the tongue are not necessarily a precursor to AIDS and need to be examined for a definitive diagnosis. Small bubbles under the tongue may be caused by red, swollen and congested papillae of the tongue mucosa or cysts of the tongue mucous glands. There are scattered papillae distributed on the normal tongue mucosa, including filiform papillae, fungal papillae, contour papillae and leaf-shaped papillae. If the ratio of the tongue flora in the mouth is imbalanced, it will cause the papillae to be red, swollen and congested, which will be manifested in the form of small blisters. In the case of isolated vesicles, there is also the possibility that they may be due to an acute mechanical irritation injury that ruptures the mucous glandular vesicles, followed by the formation of a mucous cyst. However, if the appearance of clear vesicles in the oral cavity is accompanied by persistent low-grade fever, chronic diarrhea, weight loss, fatigue, generalized lymph node enlargement, gingivitis and periodontitis, etc., then there is a high degree of suspicion of AIDS, and it is necessary to be admitted to the hospital in time for the serum anti-HIV antibody test, so that the diagnosis can be clarified and then treated promptly. In addition, patients need to pay attention to avoid adverse stimuli, eat light and easy to digest food, and maintain a regular lifestyle, avoid excessive overtime work and stay up late.