Patients who have been definitively diagnosed with oral cancer are best advised not to consume alcohol, which can be classified into the following situations: First, patients in whom oral cancer is discovered late and who are unable to undergo curative surgery still have cancerous lesions present. The vasculature of the tumor surface is relatively fragile, and drinking alcohol can cause damage to the local mucosa, leading to significant pain and even bleeding. Second, patients who have been diagnosed early with oral cancer and have undergone surgery will have scar tissue formation locally. Drinking alcohol can cause further damage to the mucosa and even irritate the scars. Third, patients who receive radiation therapy for oral cancer have normal oral mucosa that is already susceptible to radiation damage. Drinking alcohol at this time can exacerbate this type of radiation-induced mucosal damage.