The successful rate in producing oral candidiasis of the animal is not high. By utilizing: (1) fresh cell-line isolated from the oral cavity of the patient suffering from oral candidiasis and passing twice in rabbits and re-isolated to increase its toxicity; and (2) expanding the area of examination, the authors successfully (100%) produced oral candidiasis in Wistar rats. The specimens are studied histologically on its nature of whether it is a precancerous lesion or not.