Traditionally, the use of organic compounds as cigarette flavors has been approached through the art of experienced flavorists. Flavors are applied to test products which are evaluated by expert smokers or consumer panels to determine if the added ingredients improve the flavor quality of the smoke. This approach has been very successful in the creation of new smoking products. However, this artistic approach does not provide much understanding of the fate of flavoring materials whether added to and/or naturally present in the tobacco. Analytical studies of flavor ingredients provide information on what happens to these materials during smoking and may suggest ways of more efficient usage. Analytical methods will be discussed briefly and some of the results obtained in a study of phenylacetic acid as a cigarette flavor will be presented. An analytical procedure was developed to measure the amount of phenylacetic acid on cigarette tobaccos, filters, and smoke. Phenyl acetic acid is converted to its trimethylsilyl ether and subsequently analyzed by high resolution gas chromatography on a 30 m x 0.32 mm DB-5 fused silica column. Detection is accomplished with a flame ionization detector. Through the use of this method, phenylacetic acid is shown to transfer from tobacco to mainstream and sidestream smokes at levels of 21 and 13%, respectively, for the sample tested. Puff-by-puff analyses for mainstream smoke delivery of phenylacetic acid will also be presented. These results show little filtration of phenylacetic acid from mainstream smoke by the tobacco rod. In addition to the preceding results, data will be presented concerning the distribution of radioactivity from 14C-labeled phenylacetic acid added to cigarettes prior to smoking. These results confirm those obtained in the unlabeled smokings and furthermore show that most of the radiolabel ends up in the sidestream gases.