Hidden pain on the left side of the lower part of the stomach may be caused by improper diet, inflammation, intestinal tumors, etc. You can choose to adjust the diet, glucocorticosteroid therapy such as aminosalicylic acid, surgical treatment and other options. It is recommended to go to the hospital in time. 1. Hidden pain on the left side of the lower part of the stomach caused by improper diet: avoid eating spicy, cold and greasy food, and eat fresh and nutritious food, such as green leafy vegetables, fruits, and diluted rice. 2. Hidden pain on the left side of the lower part of the stomach caused by inflammation: general treatment through analgesia, antidiarrhea, electrolyte supplementation and rehydration. According to the actual condition of the patient, choose aminosalicylic acid, salazosulfapyridine, glucocorticoids and other drug treatment. If necessary, choose surgical treatment. 3. Hidden pain on the left side of the lower part of the stomach caused by tumor: If it is caused by tumor, generally speaking, it is better to choose surgery to remove the tumor, and if necessary, combine with radiotherapy and chemotherapy treatment. If the pain is repeated, it is recommended to go to the hospital in time and apply medicines under the doctor’s guidance to standardize the diagnosis and treatment.