The European Food Safety Authority was asked to provide scientific advice on two studies, namely a carcinogenicity study in mice (Soffritti et al., 2010) and a prospective cohort study on the association between intakes of artificially sweetened soft drinks and preterm delivery (Halldorsson et al., 2010) and to conclude on the need to revise previous evaluations of aspartame or of the other sweeteners authorised in the European Union. The study by Soffritti et al. (2010) is a long-term carcinogenicity study in mice with transplacental exposure to the artificial sweetener aspartame. The authors concluded that, based on their results, aspartame induces cancer in the livers and lungs of male Swiss mice. EFSA has evaluated this carcinogenicity study and has concluded that, on the basis of the information available in the publication, the validity of the study and its statistical approach cannot be assessed and that its results cannot be interpreted. Furthermore, in view of the generally recognised lack of relevance for human risk assessment of the type of tumours observed in Swiss mice when they are induced by non-genotoxic compounds, EFSA concluded that the results presented in Soffritti et al. (2010) do not provide a sufficient basis to reconsider the previous evaluations by EFSA on aspartame. Halldorsson et al. (2010) investigated preterm delivery in a cohort of 59 334 pregnant women. The authors concluded that their results show an association between intake of artificially sweetened soft drinks and preterm delivery in the cohort. EFSA assessed this study and concluded that there is no evidence available to support a causal relationship between the consumption of artificially sweetened soft drinks and preterm delivery and that additional studies are required to reject or confirm an association. Overall, EFSA concluded that the information available from the Soffritti et al. (2010) and Halldorsson et al. (2010) publications do not give reason to reconsider the previous evaluations of aspartame or of other food additive sweeteners authorised in the European Union.