No, you should not smoke before surgery. Smoking can make breathing harder during and after surgery, raise the risk of pneumonia, slow healing, and increase the chance of infection and heart problems. Quitting helps even if it is close to surgery, and the earlier you stop, the better. One source says it is best to quit a week or more before surgery, and another says quitting at least 4 weeks before surgery can lower breathing and wound-healing risks. For marijuana, one source says not to use cannabis products within 72 hours of general anesthesia, and another says it is not advisable to smoke marijuana on the day of surgery. Verify the exact plan with your surgical or anesthesia team in case they want something different for you.