OBJECTIVE: The potential role of acidic drinks in the aetiology of dental erosion is well recognized. Whilst the wide-scale consumption of bottled waters is unlikely to contribute significantly to erosion, the role of flavoured sparkling water drinks is unclear. The aim of this study was to determine the pH, titratable acidity and in vitro erosive potential of a selection of these drinks drawn from the UK market to identify what dietary advice would be appropriate in relation to their consumption. METHODS: pH was measured using a pH electrode and titratable acidity recorded by titration with 0.1-m NaOH. Erosive potential was assessed using an in vitro dissolution assay with hydroxyapatite powder and electron microscopic examination of surface enamel of extracted human teeth, following exposure to the flavoured sparkling waters for 30 min. RESULTS: All of the flavoured waters tested showed appreciable titratable acidity (0.344-0.663 mmol) and low pH (2.74-3.34). In the hydroxyapatite dissolution assay, all of the waters demonstrated erosive potential (89-143%) similar to or greater than that of pure orange juice, an established erosive drink. Exposure of the extracted teeth to the flavoured waters resulted in surface changes consistent with erosive dissolution. CONCLUSIONS: Flavoured sparkling waters should be considered as potentially erosive, and preventive advice on their consumption should recognize them as potentially acidic drinks rather than water with flavouring.