Amidino compounds represented by the formula ##STR1## and pharmaceutically acceptable acid addition salts thereof are novel compounds and are useful as powerful anti-trypsine, anti-plasmin, anti-kallikrein and anti-thrombin agents. Having strong anti-Cl (Clr, Cls) activities and an anticomplement activity, they are also useful as anticomplement agents. These amidino compounds are prepared by usual esterification of carboxylic acid compounds represented by the formula (II)R.sub.1 --COOH (II)with amidinophenol compound (III) and, if necessary, can be transformed into pharmaceutically acceptable acid addition salts thereof. ##STR2##