Key takeaways:

Nitrous oxide (N2O) is a gas medication that healthcare teams use for anesthesia.
N2O is very safe, and providers often use it with other anesthetic medications to provide adequate pain relief.
N2O can cause long-term health conditions if someone uses it consistently, so it’s best not to use it recreationally.

Nitrous oxide (N2O) is an odorless, colorless gas healthcare providers use in anesthesia. There are many types of gas that work for anesthesia. N2O is the weakest among them. Because it isn’t very strong, providers often use N2O with other medications to provide complete pain relief during a procedure. But even though it isn’t the strongest pain reliever, it’s pretty versatile because it works quickly and has limited side effects. Healthcare teams can use N2O during dental procedures, surgeries, and even during labor. If you’re having a procedure and your provider offers you the option of N2O, here’s everything you need to know about “laughing gas.”

What happens when I take nitrous oxide?

N2O is a gas, so if you’re getting it for anesthesia or sedation, you’ll inhale it from a mask. The mask looks the same as the ones that deliver extra oxygen or nebulized medications like albuterol.

You’ll feel the effect of N2O almost immediately. Breathing in N2O makes you feel lightheaded, happy, and even giddy. This is why N2O is commonly known as “laughing gas.”

Just like other medications, providers can give N2O in different doses. Doses for oral or intravenous (IV) medications are usually in milligrams (mg), but a dose of N2O comes as a percentage.

The dose of N2O that’s used during a procedure varies. At the lowest doses, you’ll only feel lightheaded, but as the dose goes up you’ll feel sleepy and experience pain relief. For example, inhaling 30% N2O provides the same pain relief as taking 10 to 15 mg of morphine.

At higher doses, people experience even greater pain relief. But at doses over 50%, you can lose consciousness. That’s why in certain situations — like during labor — the maximum dose you can get of N2O is 50%. If that isn’t enough to control your pain, your team will need to add a different medication.

When your procedure is over, your team may give you pure oxygen for a few minutes through the mask. This helps remove any remaining N2O from your body. Then they will remove the mask from your face. Recovering from N2O anesthesia is very fast. You’ll notice that the effects of the gas wear off within 1 or 2 minutes, and then you’ll feel back to normal.

Unlike other types of anesthesia, you might be able to drive yourself home after receiving N2O.

What are the negative effects of nitrous oxide?

Most people don’t experience any side effects from N2O, especially if they only need it for a short procedure. But like all medications, it can cause some side effects, including:

Nausea and vomiting
Headaches
Dizziness

Who shouldn’t use nitrous oxide?

In certain situations, N2O isn’t a safe option for anesthesia. These situations include:

Air trapping inside the body: If you have a medical condition that causes extra air to be trapped inside your body, you shouldn’t receive N2O. N2O enters an air-filled space 30 times faster than air can come out. This causes the space to expand, which can be dangerous. If you have a pneumothorax or a small bowel obstruction, you shouldn’t get N2O.
Specific surgeries: Certain surgeries put air into the body as part of the procedure. This includes many laparoscopic surgeries, middle ear surgeries, and certain types of retinal surgeries. If you are having one of these procedures, you shouldn’t get N2O. N2O isn’t used during certain head or neck procedures either. Specifically, if your team will be using an electrocautery, they can’t use N2O because the cautery can spark a fire.
Early pregnancy: Because N2O can block vitamin B12, people who are in their first trimester are advised not to use N2O. Even though there’s some evidence that N2O may not actually cause harm in early pregnancy, most people and providers prefer to avoid the risk.
Severe heart conditions: If you have a history of heart failure or severe heart disease, your team will likely advise against using N2O. N2O causes the heart to pump with slightly less strength. Usually the heart can keep up with your body’s oxygen needs anyway. But if you have a history of heart failure, your heart may not be able to overcome the effects of N2O.

Is nitrous oxide safe for recreational use?

N2O has become a popular recreational drug because of its euphoric effect. In the U.K., it’s already the second most popular recreational drug after cannabis.

Although N2O is safe to use as an anesthetic in a clinical setting, when used long term it can cause serious health problems, including:

Injuries: N2O makes people dizzy and disoriented, which has led to various kinds of accidents, resulting in minor and serious injuries.
Brain damage: When providers use N2O as anesthesia, you get extra oxygen at the end of the procedure to get rid of all the N2O in your body. This is because N2O decreases oxygen in the lungs. During recreational use, you don’t replace the oxygen that’s missing from your body. Lower oxygen in the body can cause brain damage and even death in certain situations.
Nerve damage and anemia: N2O blocks vitamin B12 from working. Your body needs vitamin B12 to make nerve tissue and red blood cells. Without vitamin B12, you can develop nerve damage and anemia. Numb fingers can be the first sign of nerve damage from N2O use.

Bottom line

Healthcare teams have used nitrous oxide as an anesthesia medication for almost 200 years. It’s safe, works quickly, and has few side effects. But it isn’t the strongest pain reliever, so you might need additional medications during your procedure to provide complete pain relief. Most people can safely receive nitrous oxide during a procedure and have a short recovery time with few, if any, side effects. Although its popular name — “laughing gas” — makes it sound harmless, recreational use can lead to serious complications.

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Written by:

Ronald W. Dworkin, MD, PhD

Ronald W. Dworkin, MD, is a board-certified anesthesiologist who has been practicing anesthesiology in a community hospital for 30 years. He has taught in the honors program at George Washington University for over 10 years and works as a senior fellow at the Hudson Institute.

Edited by:

Patricia Pinto-Garcia, MD, MPH

Patricia Pinto-Garcia, MD, MPH, is a medical editor at GoodRx. She is a licensed, board-certified pediatrician with more than a decade of experience in academic medicine.

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