Long-distance drivers in Turkey are forced to drive continuously for 15-20 h on intercity roads without sleep or assistant drivers in order that their cargo, comprising perishable goods (e.g. vegetables, fish), can be transported to their destination on time. During long journeys, drivers try to suppress their need for sleep by using substances containing caffeine as they do not want to stop for a rest. The aim of this study was to evaluate the use of gripin by long-distance drivers and its adverse effects. This cross-sectional study was conducted at the resting facilities of the Kirikkale-Ankara highway in December 1999.Sixty-five percent of long-distance drivers took gripin regularly while using their vehicles. Of these, 53.8% used gripin due to headache and 46.2% to prevent sleep. Sixty-five percent of drivers were smokers and 76.9% of smokers took gripin. It was observed that long-distance drivers tend to use substances containing caffeine in order to prevent sleep and headache.