Heparin injections do not cause abdominal pain. Heparin is mainly injected subcutaneously and can pierce into the fat layer without affecting the intestine. If mild abdominal pain occurs, it can be manifested as a tingling sensation in the skin, and there can be subcutaneous bruising, which is related to untimely compression and does not require special treatment and can improve on its own. If the abdominal pain is persistent, it may be caused by problems other than heparin, such as cold stimulation of the abdomen, which may cause paroxysmal abdominal pain and diarrhea. Consider going to the hospital for abdominal CT examination and stool routine to clarify. If there is no obvious abnormality, most of them will be relieved significantly after taking oral medication to adjust the gastrointestinal function. When injecting heparin, be sure to pay attention to regular coagulation four tests.