Mouth ulcers can usually drink lemonade, but should be avoided when mouth ulcers are severe or when lemonade is too acidic. Mouth ulcers are diseases of the oral mucosa, often with ulcers, pain and other symptoms. Mouth ulcer patients can generally drink lemonade, but lemonade vitamin C, citric acid content, belong to the acidic substances, a single large amount of drinking or lemonade acidity is too high, may stimulate ulcers, so that the pain is aggravated. In addition, patients with severe mouth ulcers should avoid drinking lemonade to prevent irritation of the ulcers. If you have mouth ulcers, you can take cetrimide tablets, ciprofloxacin tablets and other medications to sterilize them, and use tretinoin oral paste, dexamethasone ointment and other medications to reduce the pain. But the specific use of drugs should be under the guidance of a doctor, do not blindly use their own drugs. In addition, before the ulcer heals, you should avoid eating hard, spicy, too salty, too sour or too hot food.