Glycaemic responses to the dextrin NUTRIOSE®6 (Dex) and the MALTISORB® maltitol (Mal) have been studied previously but their effects on vigilance and cognitive performances are still not known. The present study assesses dose-related glycaemic responses following Dex administration and the hypothesis that Dex and Mal could modulate the glycaemic response, improve vigilance under stress conditions and improve cognitive performances in rats. The glycaemic responses following Dex and corn syrup GLUCIDEX®IT 21 (CoS) solutions at 0·3, 0·5 and 1·0 g/kg body weight administered by oral administration (experiment 1) and glycaemic responses to three cereal bars (standard (CoS), Dex or Dex/Mal bar) (experiment 2) were evaluated. Rats having eaten cereal bars were submitted to vigilance and aversive light stimulus avoidance conditioning tests to assess their vigilance and cognitive performances. The first experiment showed that the glycaemic response to both products is dose-related and that CoS induced a glycaemic response three times higher than the Dex response. The second experiment showed the same glycaemic response for the three cereal bar-treated rats. Yet, an increase in the vigilance of Dex/Mal-treated rats as well as a better discrimination between two levers in the cognitive test for Dex- and Dex/Mal-treated rats were noticed. These results suggest that the glycaemic response is not the only factor to be considered in predicting the efficiency of a food ingredient on vigilance and cognitive performances: these behaviours are improved after Dex- and Mal-prepared cereal bar ingestion whereas the glycaemic response does not differ from the CoS-prepared bar.