General anesthesia involves the use of medication to induce unconsciousness during surgery. The medication is either inhaled through a breathing mask or tube, or administered through an intravenous line. After you are asleep, a breathing tube may be inserted into the windpipe to maintain proper breathing during surgery. Once the surgery is complete, the anesthetic is discontinued and the patient wakes up in the operating room or the recovery room. Possible side effects include nausea/vomiting, sore throat, hoarseness, headache, mouth or teeth injury, awareness under anesthesia, injury to blood vessels, temporary memory loss and aspiration possibly leading to pneumonia.