A pain in the left side of the stomach is related to the gastrointestinal tract, such as acute gastroenteritis, sigmoid lesions, and pancreatitis can cause pain in the left side of the stomach. Acute enteritis caused by viral infections such as eating unclean things or getting cold can also cause left side stomach pain. For women, left side stomach pain is caused by gynecological diseases, commonly pelvic inflammatory disease, adnexitis, and even tumor diseases. Having stones in the urinary system can also cause left side stomach pain, and back pain can also occur. The left side of the stomach has organs such as intestines, kidneys, pancreas, spleen, and uterine adnexa of women appear, the left side of the stomach pain should be considered to cause lesions in these organs, the pain in the left side of the stomach can not be judged to be caused by what disease, it is best to go to the hospital to do ultrasound examination for judgment, the treatment of different diseases is different, avoid blind treatment, and delay the best treatment time of the disease, but also to consider the surrounding It is also important to consider that the peripheral tissues have lesions that can also radiate to the left side of the stomach and cause pain.