Logically, aromatic nitro and amino compounds should be discussed together because their toxic responses are often similar due to a common metabolic intermediate. Synthetically, amines are generally derived from nitro compounds, but in some cases nitro compounds can be prepared through amines when other methods fail to afford specific compounds. There are good and bad attributes to these types of compounds. Some act as sensitizers and contingent on physical properties may be absorbed through the skin or mucous membranes. They may also cause methemoglobinemia, depending on such factors as the structure and the particular organism. Some members of this class are known as animal and human carcinogens; for humans, the urinary bladder is the most prominent target organ. Nevertheless, these compounds and their derivatives have enlivened our world through their use as dyestuff intermediates or as photographic chemicals, they alleviate pain as components of widely used analgesics, and they cushion or insulate us through their use in flexible and rigid foams. Other important uses include production of pesticides, including herbicides and fungicides, as ingredients in adhesives, paints and coatings, antioxidants, explosives, optical brighteners, rubber ingredients, and as intermediates in many other products.