Also known as Sodium Lauryl Sulphate or Sulfate, this detergent (surfactant) is used in shampoos for its cleansing and foam-building properties. Often derived from petroleum, it is often poetically referred to with the phrase "comes from coconuts." It can cause ulcers, eye irritation, scalp scurf similar to dandruff, skin rashes and other allergic reactions. A contaminant of the chemical can be 1,4 dioxane, a probable carcinogen.