Anesthesia Side Effects: What to Expect & How to Stay Safe

Surprising but true: up to about 30% of people have nausea after general anesthesia. Side effects vary a lot depending on the type of anesthesia, your health, and the procedure. Knowing what’s common and what’s rare helps you feel less anxious and more prepared.

First, a quick map: general anesthesia makes you fully unconscious, regional (like spinal or epidural) numb large areas, and local numbs one small spot. Each has its own side effect pattern, and most reactions fade in hours or days. Still, some issues need attention right away.

Common short-term effects and quick fixes

Nausea and vomiting: this is the most common complaint after general anesthesia. Drugs to prevent nausea are often given during surgery. If you feel sick, tell staff so you can get anti-nausea medicine and small sips of clear fluids once allowed.

Sore throat and hoarseness: a breathing tube can irritate the throat. Warm drinks, throat lozenges (if allowed), and time usually fix it within a few days.

Shivering and cold: anesthesia can lower body temperature. Blankets, warm fluids, and gentle heating help. If shaking is severe, staff can give medication.

Drowsiness, dizziness, and blurred vision: common for a day or two. Avoid driving, heavy machinery, or signing important documents until you’re fully alert.

Pain at the injection site or temporary numbness: regional blocks can leave a patchy numb area for hours. Ice, elevation, and following pain-med instructions will help. Persistent numbness past a week should be checked.

Serious but rare risks and when to call

Allergic reactions: hives, swelling, or trouble breathing require immediate emergency care. Tell staff about allergies before surgery so safer drugs can be chosen.

Breathing or heart problems: anesthesia teams monitor breathing, oxygen, and heart function closely. After you leave the hospital, call emergency services if you have severe shortness of breath, chest pain, or fainting.

Malignant hyperthermia: a rare, life-threatening reaction to certain anesthetics causes high fever, muscle stiffness, and rapid heart rate. It usually appears during or right after surgery and is treated in hospital—report a family history of bad reactions to anesthesia.

Postoperative cognitive changes: older adults can have confusion or memory problems for days or weeks (delirium or post-op cognitive dysfunction). Keep family members informed, and schedule follow-up with your doctor if mental changes persist.

Nerve injury: rare but possible with regional blocks or positioning during long surgeries. If you have new weakness, numbness, or severe pain that doesn’t improve, get checked.

To reduce risks, be honest about medications (especially blood thinners, diabetes drugs, and herbal supplements), stop eating as instructed, avoid alcohol, and arrange a ride home. Follow discharge instructions: hydrate, move slowly, take prescribed meds, and keep follow-up appointments.

Most side effects are short-lived and manageable. If you’re unsure about a symptom, call your surgeon or anesthesiologist—early calls often prevent bigger problems. Knowing what to expect makes recovery smoother and less stressful.