We investigated the gastric emptying of a small solid meal in 21 healthy middle-aged men. Nine heavy smokers and 12 non-smokers were studied with a scintigraphic technique, using 99Tc-tin colloid as a tracer. All subjects had been instructed to abstain from smoking for at least 10 h before and during the examination. Smokers had on an average a shorter gastric emptying half-time (24.2 +/- 8.5 min) than non-smokers (40.6 +/- 14.1 min) (p less than 0.01). We conclude that habitual smoking has not only acute effects on gastric emptying but also a more long-standing influence.