Tsistamin (Cystaminum dihydrochloricum; list B) is a drug which reduces the intensity of the total radiation reaction when exposed to the body of ionizing radiation; dihydrochloride bis-(beta-amino-ethyl)-disulfide. Applied for the prevention of radiation sickness when rentgenoterapii malignant tumors. Tsistamin assign inside for 1 hour before irradiation. The irradiation of abdominal cavity and small pelvis tsistamin appoint daily 0.6 g; in the exposure of the head, neck and chest in the total dose of radiation 5000 R - 0.6 grams a day, with the dose of 12 000 R - 0.6 g daily. By reducing the number of cells to 4000 1 mm3 dose of applied increase to 0.8, Tsistamin used during the entire course of radiation therapy. When developed radiation sickness (severe leukopenia), therapeutic effect does not. The form of release: tablets to 0.2 and 0.4,