This study was undertaken to investigate the antifungal effect of DL-limonene on yeasts using disk diffusion and the minimum inhibitory concentration (MIC). The effect of DL-limonene on ethyl alcohol fermentation by Saccharomyces cerevisiae was also investigated. According to disk diffusion results, the development of an inhibition zone was observed in all microorganisms tested. The inhibition zones were larger than those occurring with the Fungizone antibiotic used as the control. Inhibition zone diameters increased with increasing amounts of DL-limonene. MIC results varied between 500 and 4000 mu g mL(-1) depending on the yeast strain. DL-limonene at a concentration of 0.20% (w v(-1)) inhibited cell growth, ethanol formation, and sugar utilization by S. cerevisiae.