Most laundry detergents are formulated with enzymes to get the most common stains out. These products are called 'biological' detergents.
Enzymes are obtained from selected strains of bacteria. Products that contain enzymes can be irritating to the skin and cause allergic reactions such as asthma and dermatitis. Although the addition of enzymes is promoted as the best way to get rid of 'protein' stains such grass, chocolate and blood, this is somewhat misleading. The most common clothing stains are not due to protein, but are dirt and grease stains. When you use these specially formulated products, you are often paying for the money they have spent on advertising unnecessary additives to you on TV. Enzymes don't have to touch your skin to cause an allergic reaction. In the December 2000 issue of The Lancet (vol 356: 1899-1900), there was a letter reporting an outbreak of asthma in a detergent factory due to inhaling airborne enzymes.