The inhibitory collagenolytic activity (47—64% inhibition in 0.22—0.24 μM) of fukinolic acid and cimicifugic acids A, B, and C, which are esters of fukiic acid (3',4'-dihydroxybenzyl tartaric acid) was more potent than that (20—37% inhibition in 0.23—0.24 μM) of cimicifugic acids D, E, F, which are esters of pscidic acid (4'-hydroxybenzyl tartaric acid). Since fukiic acid showed weaker inhibition, and caffeic acid, ferulic acid, isoferulic acid, and p-coumaric acid showed far weaker activities, the entire structures of fukinolic acid and cimicifugic acids A, B, and C proved to be responsible for the inhibitory activities. Trypsin and pronase E hydrolyzed collagen nonselectively alone or in addition to collagenase. These collagenolytic activities were also inhibited by fukinolic acid. These results show that fukinolic acid may inhibit either the collagenolytic activities specific to collagenase or nonspecific to other emzymes. The present studies suggest the potential effect of fukinolic acid and cimicifugic acids of Cimicifuga rhizomes in preventing collagen degradation by collagenases or collagenolytic enzymes under pathological conditions, wound healing, or inflammation.