Hematidrosis is an eccrine sweat disorder characterized by one or more episodes of spontaneous, bloody sweating from non-traumatized skin. The author carried out a systematic review of all cases of hematidrosis reported in PubMed over the past 20 years. A total of 25 cases were reviewed; 21 were women (84%), the median age was 13 years (range 9-72), and the majority (62%) were from Asia, mainly India. Hematidrosis was located on the face-including the forehead (40%), eyes (40%), and ears (36%)-in 96% of the cases and on the umbilicus in 24% and the palms in 20%. Prodromal symptoms were reported by almost 30% of the patients. Possible triggering factors were identified in 56% of the cases; most of these (86%) were stress factors within families (conflicts or abuse) or at school. In two cases, platelet dysfunction and epilepsy were suspected as culprits. Nine patients had a psychiatric diagnosis associated with hematidrosis. The outcome was favorable in most of the cases with medical treatment (e.g., beta-blocker, anxiolytics) and psychological support. The number of cases has increased in recent years. Hematidrosis appears to be a somatization disorder that mainly affects children from developing countries. Its physiopathology remains largely unknown. It deserves better recognition because it is usually a temporary condition when managed properly.