Causes of swelling on the left side of the foot may be related to deep vein thrombosis of the lower limbs, contact dermatitis, salpingitis, soft tissue contusion and other diseases, and the treatment program is different for different causes. After twenty-four consecutive days of infusion, the swelling still does not subside, we must first improve the relevant examination to clarify the cause of the disease, and then for the cause of the treatment. 1. Lower extremity deep vein thrombosis: ultrasound examination of the veins of the lower extremities can be a clear diagnosis, and in the treatment of thrombolysis (urokinase), anticoagulant drugs (low molecular heparin) treatment. 2. Contact dermatitis: it can be clearly diagnosed through routine blood tests and clinical manifestations, and in the treatment, it is necessary to choose anti-allergic and anti-itching drugs, such as loratadine tablets. According to the needs of the condition, glucocorticoid drugs can also be used for a short period of time to improve the symptoms, such as methylprednisolone succinate injection. 3. Danovirus: It can be clearly diagnosed through clinical manifestations, blood tests and C-reactive protein tests, and sensitive antibiotics need to be selected for treatment, such as cefuroxime sodium, amoxicillin clavulanate potassium, levofloxacin and so on. 4. Soft tissue contusion: the diagnosis can be clarified through history and imaging examination, and anti-tissue edema drugs, such as sodium heptaphyllum saponin, should be chosen for treatment. In the case of the etiology is not clear, blind use of drugs not only can not achieve the therapeutic effect, but will increase the adverse effects of drugs, so we must improve the relevant examination as soon as possible, as soon as possible to clarify the cause of the disease, and then for the cause of the treatment.