A method for the determination of dimethyl fumarate (DMF) in desiccant and antimould sachets, employed for protecting consumer products from humidity and mould, has been developed. The method is based on a solid–liquid extraction followed by HPLC-UV analysis. The method was validated with respect to recovery, linearity, limits of detection and quantitation and precision. The recovery was 98%. The correlation coefficient value (r) was equal to 0.94. Both intra- and inter-day precisions were studied at several concentration levels, being satisfactory in all cases (RSD < 5). Limits of detection and quantification values were in the low microgram per gram level, thus allowing the determination of DMF at concentrations below the limit established (0.1 mg/kg) by the recent EU Directive (Decision 2009/251/EC). The proposed procedure was applied for the determination of the target compound in 41 desiccant and antimould samples. DMF was detected in 39.0% of samples and its content in many samples exceeded the legal limits. The results of our analysis highlight the high risk of exposure to this powerful allergic sensitizer for consumers. Copyright © 2011 John Wiley & Sons, Ltd.