The purpose of this study was to determine the effect of IPBC(3-lodo-2-propynylbutylcarbamate) on dandruff caused by the anthropophilic fungus Malassezia furfur. The effects of IPBC on dandruff were examined by evaluating (a) the MIC value of IPBC using broth dilution method; (b) the remnant antimicrobial activity of IPBC containing shampoo on skin disc; (c) the antidandruff efficacy of 1.0 % IPBC containing shampoo in double blind clinical trial. To investigate the remnant antimicrobial activity of IPBC against Malassezia furfur, guinea pig-skin disc was washed with antidandruff shampoo and then the diameter of inhibition zone per disc was measured. For clinical trial, thirty healthy volunteers, aged 25-35, participated in 4 week study. At 0, 2, 4 weeks, examinations of scaling, itching on scalp were carried out. The MIC(Minimun Inhibition Concentration) values of IPBC range from 0.10 to 1.00${mu}g/ml$ and it seems that IPBC is more effective in the MIC values than zinc pyrithione, selenium disulphide, piroctone olamine and comparable to ketoconazole, climbazole. When the remnant antimicrobial activity of IPBC shampoo on skin disc was determined, 0.5% IPBC shampoo and 2.0% Ketoconazole shampoo resulted in similar antimicrobial effect. In addition, 1.0%, 2.0% IPBC shampoo was more effective than 2.0% ketoconazole shampoo. After two and four-weeks of 1.0% IPBC shampoo treatment, there was significant reduction of scaling, itching in test group compared to control group. On the basis of these results, it can be concluded that 1.0% IPBC is more effective than 2.0% Ketoconazole in reducing dandruff. It seems that strong capacity of drug binding to the stratum corneum plays a role in its antidandruff effect since adsorption of active ingredients on scalp is very important factor in reducing dandruff.