Bleeding 12 hours after having an ESD procedure is sometimes serious and sometimes relatively non-serious, depending on the amount of bleeding. ESD refers to endoscopic mucosal dissection, which is mainly used for the treatment of early stage cancer and precancerous lesions, and it is possible for the trauma to bleed 12 hours after having ESD surgery. After ESD, if the amount of bleeding is relatively small and the wound is only oozing blood, the condition is not serious and the bleeding can be stopped after hemostatic treatment. After ESD surgery, active bleeding may occur on the trauma, this kind of bleeding is not oozing blood, but refers to the bleeding caused by the rupture of small blood vessels, the amount of bleeding is relatively large, and it is not easy to stop the bleeding, the condition is relatively serious at this time. Bleeding after 12 hours of ESD surgery is recommended to consult a doctor in time, under the guidance of a professional doctor to standardize the treatment, so as not to delay the condition.