Novel 2-amino-4,5-dihydro-1H-imidazole-1-carboxanilides, which are made by reacting 2-amino-4,5-dihydroimidazole with an aryl isocyanate, are made stable to rearrangement when converted to acid addition salt form, and are useful either as antihypertensive agents and/or antisecretary agents, as well as being intermediates to prepare known pharmacologically active N-aryl-N'-(4,5-dihydro-1H-imidazol-2-yl)ureas.