A disinfectant, also called a germicide, is an agent that kills, or inhibits the growth of, bacteria and other microorganisms on inanimate objects. Antiseptic is used on contaminated living tissue. Joseph Lister introduced carbolic acid (phenol) as a medical disinfectant in the 1870s. Today chlorinated phenols are used in pharmaceutical products. Chlorine and chlorine compounds are commonly used to kill bacteria, especially in water. Iodine is used in food preparation. Alcohol is an effective disinfectant. Ammonia is the most common agent in household cleaners. It also acts as a detergent (see soaps and detergents).