The effect of cigarette smoking on gastric emptying was studied in 18 healthy volunteers by means of an isotopic method. Although the observed individual reactions were fairly variable, cigarette smoking significantly delayed gastric emptying of a solid meal. Potential mechanisms of action of cigarette smoking on gastric emptying are discussed, including the role of nicotine. The method of gastric emptying measurement was shown to be reproducible in the paired studies performed in 11 subjects.