Milk can be used as vehicle for fluoride administration. The aim of this study was to investigate the lactic acid formation in dental plaque after daily intake of fluoridated milk. The study group consisted of 15 healthy schoolchildren, 6 - 15 years of age, in a double-blind crossover study design. After a one-week fluoride depletion period, 250 ml of fluoridated (5 ppm; total amount 1.25 mg F) standard milk or non-fluoridated control milk was consumed once daily together with an ordinary meal during 3 days of plaque accumulation with no oral hygiene. On the fourth day, plaque samples were collected immediately before a final milk intake and then after 30, 60 and 180 minutes. After a washout period of two weeks, the whole procedure was repeated with the corresponding fluoridated or non-fluoridated milk regimen. All samples were suspended and the sucrose-challenged lactic acid formation rate was determined enzymatically. The results showed a statistically significant (p 0.05) increase of the lactic acid levels 30 min after the intake of the standard (control) milk while no such elevation was evident after the fluoride-containing milk. No differences were found after 60 and 180 min compared with baseline for any of the milks. The findings suggest that fluoride added to milk may counteract the lactic acid formation that follows a non-fluoridated milk intake. Keywords: children, dental plaque, fluoride, lactic acid, milk