Hyperhidrosis is a rare condition in which the sweat glands secrete colored sweat, often caused by pigment-producing bacteria. The small sweat glands seldom secrete sweat, and occasionally ingestion of certain drugs or dyes can also cause color sweating. In Chinese medical literature, there are also records of yellow sweat and sweating blood. The cause: color sweating is because the sweat glands secrete colored sweat, often caused by pigment-producing bacteria, near the sweat glands often host some bacteria that can decompose sweat, decomposition output may have a certain color, as if the outflow of this color sweat, more common parts are limited to the face, armpits, but also visible in the chest and back and other places. The color of the sweat is yellow, but it can also be black, green, purple, brown or blue, etc. Yellow sweat in the armpits is often combined with axillary odor or hyperhidrosis. Many of these sweats are caused by food and drugs. For example, the sweat from iodine is light red, the sweat from internal chlorophenothiazine is red, and the sweat from melphalan injection is cyanotic. Chromhidrosis can occur at any age and can occur either continuously or intermittently. The small sweat glands inside the skin sometimes produce pigmented sweat, mostly from oral or injected medications, and dyes cause pigmented sweat from the small sweat glands, such as melphalan injections, which can make the sweat blue; iodide can make the sweat light red, and internal chlorophenothiazine can make the sweat red. There are other sources of colored sweat. When the initially colorless sweat reaches the skin surface and becomes colored, some people call it pseudocolored sweat. This is due to the secretion of sweat from the small sweat glands and the production of colored material by the action of bacteria, particularly Corynebacterium, which often live in the skin and hair of the axilla. Yellow sweat in the armpits is often combined with armpit odor. In addition, very few people with certain diseases have parasites or bacteria that produce colored substances that can cause colored sweating.