Laureth(s) are the polyoxyethylene ethers of lauric alcohol (for comparison see: Cetethe as polyoxyethylene ether of cetylacohol; steareth as polyoxyethylene ether of stearyl alcohol and others).
Polyalkylene glycol ethers are non-ionic surfactants whose lipophilic part consists of fatty alcohols (e.g. lauryl alcohol, palmitic alcohol, stearyl alcohols, etc.). The hydrophilic part is formed by short-chain polyethylene glycols (polyoxyethylene). In the designation of fatty alcohol polyglycol ethers, the inserted numbering means the average number of ethylene oxide units per mole. Laureth-5, for example, is the INCI designation for a polyoxyethylene ether with 5 ethylene oxide units per mole.
Laureth-5 carboxylic acid acts as emulsifier (changes the interfacial tension of liquids such as water and oil so that they can be mixed together) and surfactant (washing-active substance). It also has a cleansing effect on the body surface.