Quote Originally Posted by ntenny View Post
The latter, I think, for most of us. But there's a disorder called alkaptonuria that causes a developing agent related to hydroquinone to be excreted in the urine: see http://www.cmaj.ca/cgi/content/full/172/8/1002, a case study that includes a portrait of the patient developed in his urine.

Nathan, very fascinating. Thanks for this.