Although the annual consumption of chewing tobacco in the United States is 81 million pounds, 1 practically no information is available about its clinical or physiological effect or specifically about its effect on the heart and circulation. 2 To advise patients who are habitual chewers regarding chewing, it is important to know what changes in the pulse rate or rhythm, blood pressure, skin temperature (reflecting peripheral vasoconstriction), ballistocardiographic wave forms, arrhythmias, and circulation may be produced by chewing tobacco. Accordingly, men who chewed tobacco habitually were studied before, during, and after chewing both standard commercial tobacco (1.53% nicotine) and low-nicotine tobacco (0.31 to 0.47% nicotine). In addition, a questionnaire was sent to distinguished cardiologists, internists, and other physicians interested in peripheral vascular diseases to learn their experience with the effects of chewing tobacco on the heart or circulation. None had had personal experience with the effects of chewing tobacco on