Gangrene usually occurs when necrotic tissue is affected by the action of putrefactive bacteria. Often due to disease, trauma and other factors, resulting in narrowing of the arterial lumen, the lumen is blocked by blood clots, which can lead to a significant reduction in the arterial blood flow to the local tissue, resulting in cell death of local tissues, which leads to the emergence of a large area of irreversible necrosis of the tissue. Often, after the secondary infection with putrefactive bacteria, there will be local necrosis, blackening and other special morphological changes. It is common in vascular lesions, diabetic foot, gangrenous appendicitis, etc., and requires prompt medical treatment. If the gangrene is caused by the infection of putrefactive bacteria, it is necessary to remove the necrotic tissue by surgery in time, and choose strong antibiotics, such as ceftriaxone sodium, levofloxacin and other antibiotics to fight infection. Post-operative medication changes are required to promptly assess recovery as well as to promote local tissue recovery, and in severe cases, amputation may be required. If the necrotic tissue is infected by the bacteria, it is recommended to be hospitalized for active treatment.