Millipedes, sometimes called thousand leggers, are elongate, wormlike arthropods (see box) that are commonly found in soft, decomposing plant matter. 1 They do not bite or sting, but some species secrete (and in some cases forcefully discharge) defensive body fluids containing quinones such as toluquinone and p-benzoquinones and/or hydrogen cyanide that may discolor and burn human skin (Figure 23.1). Alexander 2 observed that affected skin becomes yellowish brown in color, turning to a dark mahogany brown within 24 hours. The mahogany discoloration is attributed to oxidation of quinones on contact with the skin. 3 There may be blistering in a day or two, exfoliating to expose a raw surface. 4 Radford 5 provided an excellent review of millipede burns in people. We are aware of one documented case in the U.S. wherein a child in North Carolina picked up a millipede and it sprayed 184him in the eye. A family member flushed the eyes with water which helped, but skin on the hands, as well as above and below the eye, was discolored and burned. After a couple of days, there was peeling, leaving new, pink skin (Elmer Gray, Department of Entomology, University of Georgia, personal communication). Millipedes may stain human skin. (Photograph by Dr. Vidal Haddad and used with permission.) https://s3-euw1-ap-pe-df-pch-content-public-u.s3.eu-west-1.amazonaws.com/9781315115283/d4aa87bd-69b2-4807-ab17-4356298ca4ae/content/fig23_1_C.jpg"/>