An oral care composition comprising a liquid phase containing 30% to 90%, preferably 30% to 80% by weight, based on the liquid phase, of water; dissolved tin; 200 to 2000 ppm fluoride ions, based on the oral composition; and 5 to 60% by weight, based on the oral care composition, of a C(3-5) sugar alcohol; characterised in that the content of dissolved tin [Sn] in the liquid phase is at least 750 ppm, preferably at least 1000 ppm, based on the composition; that 60 mol % or more, preferably 75 mol % or more of the content of dissolved tin [Sn] is in the formal oxidation state +II; and that the composition comprises an organic acid and ammonium cations of the Formula (I): R—NH+Ra—[(CH2)u—NH+Rb]v—Rc (I), wherein R is a saturated or unsaturated straight-chain hydrocarbon residue of 10 to 20 carbon atoms, v is an integer from 0 to 1, u is an integer from 2 to 3 and Ra, Rb and Rc are independently selected from hydrogen and —CH2CH2OH. The composition is preferably a mouthrinse. These compositions are tested in the treatment or prevention of erosive tooth demineralisation caused by food acids.