The most common complication after breast cancer surgery is upper limb edema on the affected side, the incidence of which can reach 80%, most of which is mild edema, i.e., edema is limited to the proximal part of the upper arm, and only a few occur in moderate or severe edema. The causes of upper limb edema are mainly as follows: (1) The most common cause is the destruction of the lymphatic vessels in the medial upper arm during surgery. Radical breast cancer surgery, including the removal of the axillary lymph node cluster, causes the inevitable destruction of the lymphatic vessels from the axilla to the medial aspect of the upper arm and poor lymphatic drainage. (2) The axillary vein is compressed during wound dressing. In order to make the wound at the axilla heal as soon as possible, generally when dressing the wound after surgery, the dressing is placed at the axilla to increase the pressure, so the axillary vein will be more or less pressurized, and the reflux of the upper limb will be blocked. (3) If the patient is obese and has extensive metastases in the axilla, the surgical incision will be extended to the upper arm and the cephalic vein will be ligated, resulting in a more difficult to recover edema. (4) Postoperative upper arm activity is too late. Early, forceful, planned and systematic functional rehabilitation exercises of the upper limbs after surgery can promote venous blood and lymphatic return and circulation of the upper limbs, and vice versa, the regeneration of lymphatic vessels is delayed and the edema lasts longer. (5) Long-term fluid accumulation and mild infection in the axilla. Improper wound treatment or other causes of non-healing axillary wounds, long-term fluid accumulation, or complications of mild infection can cause further destruction of residual lymphatic vessels, and if repeatedly infected, may even cause obstruction of subclavian or axillary veins, leading to the development of severe edema. (6) Recurrence and metastasis in the upper arm, upper and lower clavicle and axillary area after surgery. Recurrence and metastasis in these areas can cause local venous and lymphatic vessels to have compressive reflux obstruction, often resulting in progressive aggravation and irreversible edema. (7) Pre- or post-operative radiotherapy. Both preoperative and postoperative radiotherapy can cause venous occlusion and lymphatic vessel destruction in the radiation field, and also affect the upper limb reflux and upper limb function due to local muscle fibrosis compression of veins and lymphatic vessels. (1) Mild edema is often caused by surgical damage to the lymphatic vessels and axillary veins, which are compressed during wound dressing. (2) Timely functional exercise of the upper limbs after breast cancer surgery can reduce edema and restore normal function of the upper limbs at the same time. Generally, on the first two days after surgery, you can start to do forearm elbow flexion and extension exercises and fist clenching movements, 5-10 times each time, 5-6 times a day. On the third day after surgery, the affected upper limb can be lifted with the help of the healthy hand, so that the affected hand can be lifted to the level of the head, 3 times each time, 3 to 4 times a day. On the 4th day, the thumb of the affected limb can be squeezed by the healthy hand and the straight arm can be raised until it exceeds the head, 3 times each time, 3 to 4 times a day. On the 5th postoperative day, the affected elbow can be slowly lifted up with the healthy hand until it exceeds the head and is straightened as much as possible, 2 times each time, 3 to 4 times a day. On the 6th postoperative day, the fingertips of the affected limb could be used to gradually glide upward along the wall and gradually raise it, 2 times each time, 3 to 4 times a day. On the 7th and 8th postoperative days, the palm of the affected limb can be crossed over the head and touched to the opposite ear as far as possible, 2 times each time, 3 to 4 times a day. On the 9th postoperative day, the shoulder joint of the affected side can be used as the axis to do prerotation and postrotation circumferential activities, 2 times each time, 3 to 4 times a day. On the 10th postoperative day, you can try to lift the affected limb over the head, 2 times each time, 2 times a day. Later, the upper limb can be lifted, rotated forward, rotated backward and abducted according to the physical strength and wound healing condition. When carrying out radiotherapy, especially not to relax the exercise to minimize the edema caused by radioactive phlebitis and radioactive muscle fibrosis. (3) Usually pay attention to the protection of the affected limb, try to avoid holding heavy objects with the affected limb, do not compress the affected limb during infusion, sleep, and can be properly padded to facilitate venous and lymphatic reflux. (4) Chinese medicine is unique in preventing and treating edema of upper limbs after breast cancer surgery. In addition to systemic medication, external washing and external application of Chinese medicine can be used to improve the therapeutic effect. Products that strengthen the spleen and promote water circulation and activate blood circulation are often used, such as poria, poria, zedoary, coix seeds, psyllium, large belly skin, mulberry branch, turmeric, loofah, wei ling xian, peach kernel, curcuma, etc.