No, you should not smoke before surgery. Smoking increases your risk of complications during and after the procedure, from breathing problems under anesthesia to slower wound healing and higher infection rates. The American Society of Anesthesiologists recommends abstaining for as long as possible before and after any operation. Ideally, quitting four to six weeks beforehand cuts your rate of wound complications by 50%, according to the American College of Surgeons.
What Smoking Does to Your Body During Surgery
The two most immediate problems are carbon monoxide and nicotine. When you smoke, carbon monoxide binds to your red blood cells and reduces their ability to carry oxygen. Your body needs oxygen to survive anesthesia, maintain stable heart function, and begin healing tissue the moment an incision is made. Carbon monoxide has a half-life of five to six hours, meaning it takes 24 to 48 hours of not smoking for your blood oxygen levels to fully normalize.
Nicotine creates a separate set of risks. It triggers your sympathetic nervous system to release stress hormones that constrict blood vessels, raise your heart rate, and increase blood pressure. This forces your heart to work harder at the exact moment your body is already under the stress of surgery. Nicotine also makes your blood thicker by stimulating platelet clumping, which further reduces blood flow to tissues that need it most.
Airway Problems Under Anesthesia
Smokers have hypersensitive airways. Inhaled smoke particles cause a reflexive narrowing of the bronchial tubes, and over time, this makes the airways more reactive to any irritation, including the breathing tube placed during general anesthesia. The result is a higher incidence of coughing, breath holding, bronchospasm (sudden airway tightening), and laryngospasm, where the vocal cords clamp shut and temporarily block airflow. These events can cause dangerous drops in oxygen levels while you’re on the operating table.
Smoking also increases mucus production while simultaneously damaging the tiny hair-like structures (cilia) that sweep mucus out of your lungs. This combination leaves thick, sticky secretions sitting in your airways, raising the risk of postoperative pneumonia and breathing difficulties during recovery.
Wound Healing and Infection Risk
Every surgical wound depends on good blood flow to heal. Nicotine’s vasoconstrictive effect shrinks the small blood vessels that deliver oxygen and immune cells to the incision site. With less oxygen reaching the tissue, your body is slower to rebuild collagen, fight off bacteria, and form strong scar tissue. Smokers face higher rates of surgical site infections, wound breakdown, and weaker scars compared to nonsmokers.
This isn’t just a minor delay. Complications from poor wound healing can mean additional procedures, prolonged hospital stays, or chronic wound problems. If you quit four to six weeks before surgery and stay smoke-free for four weeks after, you can cut these wound-related complications roughly in half.
The Timeline: When to Stop
The longer you can go without smoking before surgery, the better. Here’s how the benefits accumulate:
- 12 hours before: Carbon monoxide levels drop significantly, improving oxygen delivery to your tissues. Nicotine levels decline within about two hours of your last cigarette.
- 24 to 48 hours before: Carbon monoxide returns to normal levels. Your blood can carry oxygen at full capacity again.
- 4 to 6 weeks before: Airway reactivity begins to calm down, mucus clearance improves, and your immune function at the wound site is meaningfully better. This is the window associated with a 50% reduction in wound complications.
Even if your surgery is tomorrow, stopping now still helps. The short-term improvements in oxygen delivery and reduced cardiac strain from clearing carbon monoxide and nicotine are real, even within hours.
Vaping and E-Cigarettes Count Too
Switching to a vape before surgery is not a safe workaround. E-cigarette aerosols trigger inflammation throughout the lungs, activating immune cells and releasing inflammatory signals that damage the lining of the airways. Vaping disrupts the barrier integrity of the lung tissue itself, causing cells to slough off and leaving the lungs more vulnerable. In severe cases, vaping has caused a condition called EVALI, which can progress to respiratory failure. These inflammatory effects add risk to any procedure involving general anesthesia, even if the vape liquid contains no nicotine.
If your vape does contain nicotine, you’re getting the same vasoconstrictive and cardiac effects as a cigarette, with the added lung inflammation from the aerosol chemicals.
What About Cannabis?
Marijuana use before surgery raises its own concerns. Cannabis causes a rapid heart rate, and one study found a fivefold increase in heart attack risk in the first hour after smoking it. For someone about to undergo the cardiovascular stress of surgery, that’s a meaningful danger.
Cannabis also changes how anesthesia works. Regular users require significantly higher doses of certain anesthesia drugs to reach the same level of unconsciousness, and standard brain-wave monitors used to gauge anesthetic depth become less reliable. This can make it harder for your anesthesia team to calibrate your care. You should tell your anesthesiologist about any cannabis use, even if it feels awkward, because it directly affects the drugs and doses they choose.
Nicotine Replacement Products Before Surgery
If you’re using nicotine patches, gum, or lozenges to help you quit before your procedure, stop using them at least 12 hours before surgery. These products still deliver nicotine, which means they still cause vasoconstriction and elevated heart rate. They’re useful tools for quitting in the weeks leading up to your operation, but they need to be paused on the day of surgery itself. Your surgical team can give you specific instructions during your preoperative visit.
Be Honest With Your Surgical Team
Your anesthesiologist and surgeon aren’t asking about smoking to judge you. They need accurate information to keep you safe. If you smoked the morning of surgery, they may adjust your anesthesia plan, prepare for airway complications, or in some cases recommend postponing an elective procedure. Hiding your smoking status doesn’t remove the risks. It just prevents your team from preparing for them.