The document summarizes the Ames test, which is used to assess the mutagenic potential of chemical compounds. It uses Salmonella typhimurium bacteria as a test organism to detect mutations caused by exposure to test chemicals. If the test chemical causes more reversed his+ bacteria compared to unexposed controls, then it is considered mutagenic. The Ames test is widely used in pharmaceutical, cosmetic, and food industries to screen for potentially carcinogenic chemicals. Though not 100% accurate, it is a simple, inexpensive, and effective way to identify many mutagenic and carcinogenic compounds.