PURPOSE: To provide the subject composition excellent in foamability and rinsability, low in the irritation to the oral cavity mucous membrane, also having antibacterial activity, containing an N-ethyl phosphate derivative as amphoteric surfactant.

CONSTITUTION: The objective composition contains 0.001-3wt.% of an N-(2- hydroxyalkyl-N,N-dimethylammonio) ethyl phosphate of the formula (R is 10-18C alkyl). This composition which can be prepared by mixing the above ingredient with conventional ingredients and water in an appropriate manner can be made into toothpaste, tooth powder, tooth wash, mouthwash, dental rinse, pasta for oral cavity, troche, or chewing gum, having excellent effects in terms of protein denaturation rate, palate alteration, oral cavity mucous membrane irritation, or bactericidal action.