Propylparaben is a bacteriostatic and fungistatic agent used as a preservative in cosmetic products, food and drugs. As a food additive, it has the E number E216. To increase the activity and reduce its dose propylparaben is used in a mixture with other parabens and in combination with other types of preservatives. Propylparaben is a chemical allergen capable of producing immunologically mediated hypersensitivity reactions. Chemically it is an ester of p-hydroxybenzoic acid.

Ethylparaben is produced naturally and found in several fruits and insects, where it acts as an antimicrobial agent. Ethylparaben is mainly used as antiseptics in cosmetics, food and medicine (E number E214). It is also can be used as feed preservatives and antiseptic for bacteria. Ethylparaben is readily absorbed from the gastrointestinal tract or through the skin. It is hydrolyzed to p-hydroxybenzoic acid and rapidly excreted in urine without accumulating in the body. Under the Federal Food, Drug, and Cosmetic Act (FD&C Act), cosmetic products and ingredients, other than color additives, do not need FDA approval before they go on the market. Broad concentration ranges reported in each product category in 1981 were < 0.1% and > 0.1% to 1%. Studies show the in vivo estrogenicity of MP and EP at human exposure levels, and indicate that populations exposed to large amounts of MP and EP may have a high burden of estrogenicity-related diseases.