Food colorings need to be tested before they can be used. These tests are done to make sure the coloring is not poisonous, and has no unwanted side-effects. Sometimes, different testing-bodies have different opinions on the safety of a certain coloring. In the United States, FD&C (generally indicates that the FDA has approved the colorant for use in Foods, Drugs and Cosmetics) numbers are given to approved synthetic food dyes that do not exist in nature. In the European Union, E numbers are used for all additives, both synthetic and natural, that are approved in food applications.