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By Mayo Clinic staffGeneral anesthesia blunts your body's natural inclination to keep food in your stomach and out of your lungs. That's why it's important to follow your doctor's instructions about when to stop eating and drinking prior to surgery. In most cases, you should start fasting about eight hours before your procedure.
Your doctor may tell you to take certain medications with a small sip of water during your fasting time. You may need to avoid some medications, such as blood thinners like aspirin, for at least a week before your procedure. Some vitamins and herbal remedies also keep your blood from clotting normally, so you should discuss the types of dietary supplements you take with your doctor.