Purpose: The aim of this randomised single-blind, cross-over trial was to assess the effect of tongue cleansing on morning oral malodour in periodontally healthy subjects. Materials and Methods: Ten systemically healthy non-smoker subjects (6 males, 4 females), 24-38 years of age, completed two 4-day periods of oral hygiene cessation with a 7-day wash-out period. In one of these test periods, subjects were instructed to clean their tongues with a tongue scraper 2-3 times a day. Participants presented at least 20 teeth, without cavities, overhanging restorations/prostheses or periodontitis, and had no history of previous periodontal therapy or use of antibiotics in the 3 months prior to the study. Volatile sulphur compounds (VSC; Interscan Halimeter) and organoleptic scores were measured in exhaled mouth air once a day, early in the morning, by one examiner. Comparisons were performed using Wilcoxon's signed rank test and Friedman's test (α = 0.05). Results: VSC levels at baseline were 206.3 ppb (SD 139.8) and 191.4 ppb (SD 127.7) for periods of usage and non-usage of the scraper respectively (p > 0.05). VSC levels did not change significantly during the 4 days, independent of tongue cleansing (Friedman, p > 0.05). Only at day 3 did the use of the tongue scraper lead to a significantly lower level of VSC compared with controls (131.1 ppb and 199.3 ppb respectively). No significant differences in organoleptic scores were observed between groups at baseline. During the whole experimental period, there were also no significant changes in organoleptic scores when individuals used or did not use the tongue scraper. Conclusion: Tongue cleansing with a scraper was unable to prevent morning oral malodour in the absence of tooth cleaning in periodontally healthy individuals. Schlagwörter: halitosis, oral malodour, oral hygiene, tongue