WebMD recommends that people scheduled for surgery stop drinking alcohol one month before the operation is scheduled. If this is not a viable option, individuals should limit themselves to two drinks daily.
According to WebMD, the effects of alcohol on someone under anesthesia are variable. Some are very dangerous, such as excessive bleeding and liver damage. Before surgery, patients should be up front with their doctors about how much alcohol they consume.
The British Journal of Anesthesia reports that drinking alcohol and smoking cigarettes are the most common lifestyle choices that affect surgery. Three or more drinks daily is considered heavy drinking and is risky pre-surgery behavior.