Cases of hematidrosis (bloody sweat) are extremely rare. This disease has been described in various terms and has been often tied to religious belief as stigmatization. We report a typical patient with hematidrosis in a 14-year-old girl who frequently bled from her scalp and palms, and, occasionally, from trunk, soles, and legs. The bloody sweat from her scalp contained all blood elements. Immediate biopsy after there was bleeding on her scalp showed multiple blood-filled spaces that opened directly into the follicular canals or on to the skin surface. Immunoperoxidase studies failed to demonstrate vascular nature of these spaces. Our study explained how and why there was bleeding in our patient and in patients with related conditions as described in earlier literatures. We also explained why this phenomenon was intermittent because the spaces indicated above will disappear after exuding their content but then reoccurred after the blood flow was reestablished.