Microcrystalline cellulose (Avicel®PH-302),lactose (Super-Tab®),carboxymethyl cellulose (CMC) and xylitol are added to tablet formulations of precipitated calcium carbonate to achieve rapid disintegration while maintaining sufficient tensile strength,and to allow tablets to be easy to take.We prepared tablets containing 200 mg of precipitated calcium carbonate by the direct compression method and measured their tensile strength,wetting rate and disintegration time.Though precipitated calcium carbonate gave tablets a greater hardness and disintegration time than tablets containing no precipitated calcium carbonate,the disintegration time in the human oral cavity was short enough for them to be rapidly disintegrating tablets.On investigating a correlation between disintegration time in vitro and disintegration time in the oral cavity,we found that disintegration time in vitro was a fairly good predictor of disintegration time in the oral cavity.The sensory test score for the calcium carbonate tablets was excellent.In addition,we demonstrated that it was possible to produce rapidly disintegrating tablets containing precipitated calcium carbonate produced by direct compression when CMC is used as a disintegrant and Super-Tab® and Avicel®PH-302 are used as excipients.