The authors administered orally 40, 60 and 80 micrograms of Formoterol which was developed as a new bronchodilator and 4 mg of Salbutamol which is considered to be a beta 2-selective drug, to healthy adults. Pulse rate, blood pressure and blood levels of cyclic GMP, free fatty acid, cyclic AMP, glucose and lactic acid were measured in order to evaluate efficacy and dosage of Formoterol and to compare efficacy of this drug with that of Salbutamol. As a result, it is considered that Formoterol has a strong dose dependent beta 2-effect with 40 micrograms of Formoterol almost as high as 4 mg of Salbutamol in beta 2-effect. In addition, Formoterol has almost no alpha-effect and its beta 1-effect can be considered negligible in the doses of 60 micrograms and 80 micrograms.