The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 24 flavouring substances in the Flavouring Group Evaluation 24, Revision 2, using the Procedure in Commission Regulation (EC) No 1565/2000. This revision was made required owing to the inclusion of the assessment of new toxicity data on one supporting substance, 2-acetylpyrrole [FL-no: 14.047], to support the re-evaluation of one candidate substance, 2-acetyl-5-methylpyrrole [FL-no: 14.085]. Nine of the original 33 candidate substances [FL-no: 13.100, 14.002, 14.023, 14.094, 14.107, 14.138, 14.145, 14.163 and 14.169], for which additional data were requested, are no longer supported by Industry for use as flavouring substances in Europe and will therefore not be considered any further. None of the 24 substances were considered to have genotoxic potential. These candidate substances were evaluated through a stepwise approach that integrates information on the structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. The Panel concluded that the 24 substances [FL-no: 14.085, 14.088, 14.089, 14.092, 14.093, 14.103, 14.104, 14.105, 14.106, 14.110, 14.115, 14.116, 14.117, 14.118, 14.120, 14.124, 14.125, 14.131, 14.134, 14.135, 14.136, 14.140, 14.143 and 14.150] do not give rise to safety concern at their levels of dietary intake, estimated on the basis of the MSDI approach. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been considered. Adequate specifications including complete purity criteria and identity for the materials of commerce have been provided for all 24 candidate substances.