The indications for histamine therapy are discussed briefly. The preparation of the patient, the contraindications and the technique of the therapy are given in minute detail along with the reactions of the patient during the therapeutic procedure. Histamine therapy is combined with other forms of shock and subshock therapy for refractory cases. The character of the therapeutic response varies. The authors state, 'In a few instances the results may be dramatic, but in most cases the changes are very subtle, though definitive'. Both objective and subjective changes are noted.