Abstract: The reaction of an imidazoline base of the formula: ##STR1## wherein R represents an aliphatic group comprising from 6 to 22 carbon atoms and R.sub.1 represents a substituted or unsubstituted alkyl or alkenyl group comprising 1 to 4 carbon atoms, with a carbo-alkylating agent is carried out in two stages. Initially the pH is maintained in the range 7 to 11 and subsequently it is maintained in the range 9 to 12.5. These conditions encourage at least part of the imidazoline to undergo alkylation followed by hydrolysis and further alkylation. The di alkylated amidoamines thus produced are believed to be novel. The reaction products are surfactants which exhibit very low skin irritancy and have a desirably low viscosity. They find particular application in shampoo formulations.