There may be many reasons for the swelling at the bottom of the tongue, including sublingual infection, sublingual cyst, tumor, etc., which should be treated with medication or surgery according to the specific situation, as follows: 1. Sublingual infection: most of the infection caused by oral ulcers leads to local swelling with pain, you can use oral spray or Yunnan Baiyao on the surface of ulcers to control the infection and also reduce swelling. 2. Sublingual cysts: Surgery is the first choice for sublingual cysts, removing the cysts and related glands, which can achieve the effect of eradication and prevention; if surgery is not carried out, tincture of iodine can be injected into the cystic cavity to inhibit the secretion of mucus, but it will recur. 3. Tumor: it is necessary to find out whether the swelling is benign or malignant tumor, benign tumors need to be surgically removed, while malignant tumors need to be surgically removed and postoperative radiotherapy. There may be other reasons for the swelling at the bottom of the tongue, it is recommended to go to the stomatology department of the regular hospital for examination, clear diagnosis and then carry out the corresponding treatment. The above drugs should be used under the guidance of a doctor.