Abstract: A dental mouthrinse is provided which is in the form of a clear solution saturated with respect to brushite and preferably also containing a source of fluoride ions such as to provide for example 3 to 20 ppm fluoride ions and a buffer with a molarity of for example 0.15 to 0.3M to provide a pH of 5.8 to 7.0. The mouth rinse is prepared by adding solid brushite to water to provide a solution containing excess solid brushite at a temperature of from 0.degree. to 15.degree. C, the solution is separated from excess brushite to provide a clear solution and the clear solution is allowed to come to an ambient temperature greater than 15.degree. C. Further ingredients of the mouth rinse may be added together with the solid brushite or to the clear solution after it has been allowed to come to ambient temperature. The mouth rinse is capable of recalcifying both dentine and tooth enamel and is particularly suitable for recalcifying early decayed areas in teeth.