Fifty-four species of extracts of Chinese herbal medicinal prescription were tested for the inhibitory activity of adenosine 3', 5'-cyclic monophosphate (cAMP) phosphodiesterase."Hange-shashin-to"was especially studied among these prescriptions. The inhibitory activity for this enzyme depended chiefly on Scutellaria root and Glycyrrhiza in this prescription. Ginseng acted as a synergistic component for Scutellaria root and on the other hand, Jujube acted as a mitigatory component for Scutellaria root in cAMP phosphodiesterase inhibition test.