We assessed anti-C. albicans activities of the 4 fatty acids : caproic acid, caprylic acid, capric acid and lauric acid in vitro. All four inhibited not only the mycelial but also the yeast-form growth of Candida albicans. In particular, capric acid and caprylic acid inhibited Candida mycelia growth at very low concentrations. The effects of treatment of these two fatty acids on oral candidiasis were examined using a murine model. When 50 µl of capric acid (more than 48.8 µM) was administered three times into the oral cavity of Candida-infected mice, symptom scores of tongues of the mice were significantly improved. Histological studies of the capric acid-treated animals indicated that the fatty acid suppressed mycelial growth of the fungus on the tongue surface. These results suggest that all four fatty acids, and especially capric acid, have potential as substances supporting anti-Candida treatment.