Twenty-six smokers took part in a study which examined subjective and physiological effects of switching to an ultra-low yielding cigarette (0.1 mg nicotine) for 10 days. Subjects were randomly assigned to one of two groups. One group continued smoking their usual brand while the other group switched to the low yielding cigarette. Subjective ratings and physiological measures were taken at baseline, then after 1, 3 and 10 days in the respective conditions. Plasma nicotine concentrations dropped by some 60% after switching. Although substantial, this drop was considerably less than the drop in nominal yield of the cigarettes (around 90%), indicating marked compensation on the part of these smokers. Switching to the low yielding cigarette was accompanied by a significant increase in hunger and a drop in heart rate. These effects typically occur following cigarette withdrawal. However, other common cigarette withdrawal symptoms, such as irritability, depression, and inability to concentrate, were not detected.