Monascus is one of the traditional fermentation fungi and has been used in many kinds of food for thousands of years. Although Monascus-fermented red mold rice performs cholesterol-lowering effects, blood pressure-lowing effects, and antioxidant effects, another metabolite, nephrotoxic and hepatotoxic citrinin, causes the concerns for safety. Various citrinin concentrations (1, 2, 10, 20, and 200 ppm) in the red mold rice are, respectively, estimated for safe use in animal tests. According to the results of serum biochemistry assays of liver and kidney in each group, citrinin did not reveal any nephrotoxicity and hepatotoxicity. Furthermore, the results of histopathological slices of liver and kidney in each group did not show any significant differences from control histopathological findings. As a result, we presume that citrinin concentrations in Monascus-fermented products within 200 ppm will not affect the functions of liver and kidney or cause any nephrotoxicity and hepatotoxicity. According to safety factor, it is proposed that 2 ppm citrinin in Monascus-fermented products may be a safe concentration.