To determine biosafety of fluorosilicic acid as a source of fluoride, we carried out acute toxicity and general pharmacological studies using mouse. Fluorosilicic acid had little effects on general behavior, pain response, convulsion, skeletal muscle function and intestinal mobility as compared to controls. It had either little adverse effects on alkaline phosphatase and collagen levels in osteoblast cells. This study supports the safety of fluorosilicic acid in animals.