The most common causes of hidden pain in the left abdomen downward are the following: First, colon tumors, colon and rectum are located in the left abdomen downward, so if there is colon cancer or rectal cancer in the left abdomen, it will lead to hidden pain in the left abdomen, often accompanied by diarrhea, blood in the stool, poor nausea and wasting, and colonoscopy can be done to clarify the diagnosis. Secondly, urinary tract stone, manifested as left abdominal hidden pain, pain sometimes dissipates to the perineum, often accompanied by left lumbar pain, it is recommended to improve the routine urine examination, urinary tract ultrasound or CT examination. Third, if a woman has hidden pain down the left abdomen, she should be alert to diseases of the adnexa, such as adnexitis, adnexal tumors, and in young women, ectopic pregnancy, so it is recommended to seek timely medical attention from the gynecology department. Fourthly, if inflammation of the large intestine occurs, it will also cause hidden pain in the left abdomen, often accompanied by blood in the stool and diarrhea, so routine stool examination and colonoscopy can be done to assist in the diagnosis.