Cigarette smoke contains over 4000 substances, some of which are harmful to the smoker. Some constituents cause cardiovascular problems, increasing the blood pressure, heart rate, and the systemic vascular resistance. Some cause respiratory problems, interfering with oxygen uptake, transport, and delivery. Further, some interfere with respiratory function both during and after anesthesia. Some also interfere with drug metabolism. Various effects on muscle relaxants have been reported. Risk of aspiration is similar to that of nonsmokers, but the incidence of postoperative nausea and vomiting appears to be less in smokers than in nonsmokers. Even passive smoking effects anesthesia. Best is to stop smoking for at least 8 weeks prior to surgery or, if not, at least for 24 hours before surgery. Anxiolytic premedication with smooth, deep anesthesia should prevent most problems. Monitoring may be difficult due to incorrect readings on pulse oximeters and higher arterial to end tidal carbon dioxide differences. In the recovery period, smokers will need oxygen therapy and more analgesics. It is time that anesthesiologists played a stronger role in advising smokers to stop smoking.