Choleth(s) are the polyoxyethylene ethers of cholesterol (for comparison see: laurethe as polyoxyethylene ether of lauryl alcohol; steareth as polyoxyethylene ether of stearyl alcohol and others).
Polyalkylene glycol ethers are non-ionic surfactants, the lipophilic part of which 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. Choleth-20 is the INCI designation for a polyoxyethylene ether with 24 ethylene oxide units per mole. Choleth-24 acts as an emulsifier.