Dantron (1,8-dihydroxyanthroquinone, danthron, chrysazin) - Poop, red urine, and cancer

• stimulant laxative banned in the USA because Americans think it causes cancer, restricted to use in palliative care in the UK because Britons think it might possibly cause cancer, and widely used in a bunch of other countries that apparently either think it to be safe or else don't really care that much
• a stimulant laxative is something that makes you poop by stimulating peristalsis, and represents the most severe type of laxative you can get, generally only being used in extreme not-being-able-to-poo situations
• has been shown to cause liver cancer in mice and colon cancer in rats, suggesting that it probably does something bad to people
• a derivative of anthraquinone, an excitingly symmetrical structure of carbon and oxygen that is used to make dyes, speed the production of wood pulp, and make seeds taste nasty so that birds won't eat them
• similar poop-inducing derivatives of anthraquinone can be found in a number of plants that have seen use as laxatives (aloe, senna, rhubarb, cascara sagrada, etc.)
• found naturally in several species of plants and insects, including the ever-popular elm-leaf beetle (Pyrrhalta luteola)
• turns your pee red
  
• has been shown to reduce neuronal injury induced by a number of bad things, including beta-amyloid (25-35), which has a role in Alzheimer's disease
• also used as an antioxidant in synthetic lubricants and as a fungicide to obliterate powdery mildew
  

- Kwon YS et al. Danthron inhibits the neurotoxicity induced by various compounds causing oxidative damages including beta-amyloid (25-35) in primary cortical cultures. Biol Pharm Bull. 2004 May;27(5):723-6.
- Danthron (1,8-dihydroxyanthraquinone). Report on carcinogens : carcinogen profiles / U.S. Dept. of Health and Human Services, Public Health Service, National Toxicology Program. 2002;10:76-7.
- http://en.wikipedia.org/wiki/Anthraquinone
- http://en.wikipedia.org/wiki/Dantron