The Ames test is used to determine the mutagenicity of a chemical compound. Substances that result in a positive Ames test are deemed mutagenic and can cause DNA mutations (i.e., changes in the DNA base pairs of a sequence) that can lead to cancer. It is routinely used in the pharmaceutical and cosmetic industries to determine a drug or cosmetics mutagenicity before moving it to the next phase in the drug-discovery or commercial production process, respectively.