The human sweat glands are divided into macrohidrosis and microhidrosis. The major sweat glands are located in the axillae, umbilicus, groin, around the anus and external genital area; the minor sweat glands are widely distributed throughout the body in addition to the skin and mucous membrane junction, with the palms of the hands and soles of the feet being the most abundant. The sweat glands may have abnormal excretion (hyperhidrosis and anhidrosis), color changes (hemohidrosis, hemohidrosis, etc.), and odor abnormalities (axillary odor, ophidrosis) due to certain diseases. Macrohidrosis chromatophobia is often limited to the face and axillae, and sweat contains more lipofuscin or hyperoxic state of lipofuscin. The onset of the disease is not significantly related to season or occupation. Facial hyperhidrosis is most commonly seen in Caucasians and is caused by ectopic sweat glands (i.e., sweat glands that grow in areas where they should not). It can occur in both men and women and is often located on the cheeks, mainly on the prominent cheekbones, but also on the forehead and eyelids. In facial hyperhidrosis, the sweat is often blue or greenish-black in color. Axillary hyperhidrosis is more common in black males and less common in Orientals. Axillary hyperhidrosis is often yellow, but can also be green, blue, or greenish-black. Small sweat gland hyperhidrosis can be confined to one part of the body, or it can spread throughout the body. The cause is different from macrohidrosis. It is caused by staining of sweat with pigments or other chemicals produced by microorganisms such as Trichoderma and Corynebacterium, and is actually a pseudo-chromatosis. For example, copper deposits on the skin surface of workers exposed to copper can stain sweat blue or green. Pseudohidrosis can occur anywhere in the body, including the sweat glands. Certain medications can cause chromhidrosis, such as methylene blue injections that can make sweat cyanotic and internal chlorophenothiazine that can make sweat red. Chromhidrosis can occur at any age, but mainly occurs during adolescence when the sweat glands are active. It can occur intermittently or persist with the activity of the sweat glands. There is also a rare form of hemohidrosis, which develops when blood or blood pigments are mixed in the sweat and excreted. It can be seen in patients with hemophilia, menstrual abnormalities, sepsis, purpura, or those suffering from severe neurological disorders. It occurs on the eyelids, forehead, chest, and genitalia, and its cause is unknown; treatment is mainly to deal with the primary cause.