A 15-year-old male patient presented with intermittent red secretion on the face, upper limbs, nail grooves, fingers and toes for more than 10 months. Ten months prior to the presentation, red secre-tions began to emerge on the face, especially ears, eyes and the surrounding area of nose, following a severe psychical stimulus. The attack typically lasted 2-3 minutes before spontaneous stop with the formation of blood crusts. The frequency was 1-4 per day during the attack of hemathidrosis which might last 1 week. The interval was irregular and varied from 10 days to months. There was no blood stasis, bruise or wound left on the skin after the wipe of bloodstain, and no itch or pain was complained of. Before the secretion of bloody sweat, the patient was always fidgety, irritable, and sometimes excited or difficult to sleep, but the secretion never occurred at night. After several episodes, bloody sweat also appeared in succession and symmetrically on the forearms, extensor crura, fingers, toes and perionychium. The cell components of bloody sweat were identical to those of peripheral blood. The patient was diagnosed as hemathidrosis. No abnormality was found in labora-tory tests, histopathological examination, electron microscopy or radiology. No relief of symptoms was achieved after treatment with vitamin C, rutoside and oryzanol. Hemathidrosis is a rare disease, and to clarify its patho-genesis is essential for its treatment. Key words: Hemathidrosis; Pathology; Microscopy; electron