Yunnan Baiyao is a world-renowned proprietary Chinese medicine developed by Qu Huanzhang in 1902 and produced by Kunming United Pharmaceutical Factory (now Yunnan Baiyao Factory) in 1956. Its ingredients contain a variety of valuable Chinese herbs, which are effective in resolving bruises and stopping bleeding, invigorating blood and relieving pain, and detoxifying and reducing swelling. The field of application of the drug is expanding, and the drug is also used externally in bulk treatment for post-operative edema in anal diseases. Immediately after the edema, a paste is made with 1 g of Yunnan Baiyao powder in warm water. A piece of sterilized gauze is opened in a sterilized medication change tray, and the adjusted Yunnan Baiyao is spread in the center of the gauze and folded with the surrounding gauze so that the paste does not spill out. After the patient’s incision is sterilized, the gauze is placed on the anus and covered with 1~2 layers of gauze and fixed with adhesive tape. So change twice a day for 3 days or stop when the swelling subsides. Yunnan Baiyao is known as “the treasure of China, the holy medicine of injury”. The main effects of Yunnan Baiyao are: resolving blood stasis and stopping bleeding, activating blood circulation and relieving pain, detoxifying and reducing swelling. In Chinese medicine, the pathogenesis of post-operative edema in the anal region is due to the downward injection of damp-heat toxins and the overflow of blood from the menstruum. Therefore, Yunnan Baiyao detoxifies the damp-heat toxin and reduces swelling, disperses the blood from the menstruum and relieves pain, and stops bleeding without creating new silt. From the pathological point of view: the causes of edema after anal surgery are divided into several categories: (1) local blood circulation and lymphatic flow obstruction; (2) surgically induced injury edema; (3) subcutaneous hematoma caused by blood leakage from the trauma surface. The pharmacological effects of Yunnan Baiyao are as follows: (1) Significantly promote platelet aggregation, shorten clotting time, wound bleeding time and prothrombin time in rats and rabbits. (2) Inhibit venous thrombosis in rats, alleviate microcirculatory disorders caused by high molecular dextran, reduce whole blood viscosity, and accelerate microcirculatory blood flow in the auricle of mice. (3) It has obvious antagonistic effect on inflammation model of animals caused by inflammation-causing factors. (4) Accelerate the proliferation of blood vessels and connective tissues and promote wound healing. Therefore, we can understand from the pharmacological action of Yunnan Baiyao: its targeted treatment of each pathological factor of postoperative edema in the anal region. Because there is a process of autologous absorption of postoperative edema in the anal region, we limit the time frame for observing efficacy to 3 days; because of this slow absorption process, if left untreated it will affect the healing of the surgical incision and the formation of new connective tissue external hemorrhoids. The use of Yunnan Baiyao for the treatment of postoperative edema in the anorectal region not only further promotes the use of Yunnan Baiyao in the field of anorectal surgery, but also provides a definitive, easy-to-use treatment for edema, the most common postoperative complication of the anorectal region.