Severe drug rash is a more serious condition with more extensive lesions, affecting the life of the patient drug rash. Specifically, the following: 1) severe erythema multiforme drug rash, which generally affects the skin mucosa; 2) herpetic epidermal necrolytic loosening drug rash, with generalized blistering and erythema; 3) erythrodermic drug rash; 4) toxic epidermal necrolytic loosening drug rash, which also has blistering and vesicles and overlaps with herpetic epidermal necrolytic loosening drug rash; this patient previously had a higher mortality rate, especially the older the patient, the higher the mortality rate. Early diagnosis and treatment is a prerequisite for patient cure, and moderate to high doses of hormone therapy are preferred. In such patients, timely cessation of the allergy-causing drugs and early and adequate use of hormones, as well as prevention of complications, protection of the gastric mucosa, prevention of pulmonary infections, and also symptomatic treatment, if the disease is severe, can be treated with gammaglobulin shock therapy.