Propylparaben, the n-propyl ester of p-hydroxybenzoic acid, occurs as a natural substance found in many plants and some insects, although it is manufactured synthetically for use in cosmetics, pharmaceuticals and foods. It is a preservative typically found in many water-based cosmetics, such as creams, lotions, shampoos and bath products. As a food additive, it has the E number E216.
Sodium propyl p-hydroxybenzoate, the sodium salt of propylparaben, a compound with formula Na(C3H7(C6H4COO)O), is also used similarly as a food additive and as an anti-fungal preservation agent. Its E number is E217.