Diabetes mellitus belongs to the category of gangrene in Chinese medicine (at first cold and numbness of limbs, then necrosis and shedding of toe joints, black rot and ulceration, long time without healing), which can be divided into internal treatment and external treatment, and internal treatment should pay attention to identification and typing, which can be divided into five types: cold and dampness blocking the collaterals, stagnation of blood veins, prevalence of dampness-heat toxin, heat toxin injuring yin, and deficiency of qi and blood. 1. For patients with cold-damp obstruction, Yanghe Tang can be used to warm yang and disperse cold (warming yang qi and dispelling cold), and activate blood circulation; for patients with blood stasis, Taohong Siwu Tang can be used to activate blood circulation and eliminate stasis (promoting blood circulation and eliminating stagnant blood in the body), and activate collaterals to stop pain (dredging the meridians and collaterals and relieving pain). In addition, for patients with dampness-heat toxicity, Si Miao Yong An Tang can be used to remove heat and dampness (to remove heat and dampness in the body), activate blood circulation and remove blood stasis; for patients with heat-poison and yin injury, Gu Bu Tang can be used to remove heat and toxins (to remove heat and toxins in the body), nourish yin and activate blood circulation; and for patients with qi and blood deficiencies, Ba Zhen Tang can be used. 2. If the wound exudate and secretion is much and smelly, it should be astringent and detoxification, and use Sanhuang fumigant decoction to impregnate or apply wet compresses; when the necrotic tissues are cleared up, to promote rapid regeneration and recovery of the wound or healing, it can be used to remove the corrosive ointment to change the medication. Discomfort should seek medical treatment in time, under the guidance of the physician’s diagnosis and selection of medication, not self-medication, so as not to delay the condition.