This paper presents a systematic review of the dental literature that was carried out to investigate whether the regular use of fluoride supplements in non-fluoridated communities during the period of tooth development increases the risk of dental fluorosis. A MEDLINE search was organized for all documents published, in English, between January 1966 and September 1997 using the following key words: fluorosis, dental, fluoride, fluoride supplement or supplements, drop or drops, and tablet or tablets. Twenty-four studies that assessed the development of dental fluorosis in children who had used fluoride supplements earlier in their life were included in this review. Of the 24 studies, 10 were crosssectional/case control studies and four were follow-up studies. These studies had data that allowed a quantitative estimation of the risk of developing dental fluorosis in users of fluoride supplements. The other 10 studies were excluded because they either did not present enough data or had other methodological problems. A qualitative review of the studies found a consistent and strong association between the use of fluoride supplements and dental fluorosis. The meta-analyses of the cross-sectional/case-control studies estimated that the odds ratio of dental fluorosis in users of fluoride supplements compared with non-users ranged between 2.4 and 2.6. The meta-analyses of the follow-up studies estimated that the relative risk in long-term users was between 5.5 and 12.2. This review confirmed that in non-fluoridated communities the use of fluoride supplements during the first 6 years of life is associated with a significant increase in the risk of developing dental fluorosis.