Cosmetics are products you apply to your body to clean it, make it more attractive, or change the way it looks. They include
Cosmetics that treat or prevent diseases are also drugs. Products such as dandruff shampoo, fluoride toothpaste, and antiperspirant deodorant are both cosmetics and drugs. A good way to tell if you're buying a cosmetic that is also a drug is to see if the first ingredient listed is an "active ingredient." The active ingredient is the chemical that makes the product effective. The manufacturer must have proof that it's safe for its intended use.
Cosmetics can cause allergic reactions. The first sign is often red and irritated skin. Fragrances and preservatives are the most common causes of skin problems.
To find out all the ingredients in a cosmetic you use, check the container. Manufacturers are required to list them. Labels such as "natural" and "hypoallergenic" have no official meaning. Companies can use them to mean whatever they want.
Food and Drug Administration
References and abstracts from MEDLINE/PubMed (National Library of Medicine)