Approved by the Cancer.Net Editorial Board, 12/2019

Anesthesia is medicine that keeps you from feeling pain during certain medical procedures. There are several different types of anesthesia. The type you receive depends on the procedure and your general health.

Types of anesthesia

Local anesthesia

Local anesthesia is an injection, also called a shot. It makes the area for the procedure numb. This means you do not feel anything there. It is also called topical anesthesia.

You usually get local anesthesia for small procedures. For example, you might have it for a biopsy, where the doctor takes a small sample of tissue. The area stays numb for up to several hours. You might be awake and alert when you have local anesthesia. Or your doctor might give you some medicine to make you relaxed and sleepy. This is called sedation, and you can learn more about it below.

Regional anesthesia

Regional anesthesia blocks pain in a certain area of the body. You get an injection, or shot, like with local anesthesia. Or you might have an IV, where the numbing medicine is given into a vein. Regional anesthesia also relieves pain after the procedure. This makes recovery easier.

There are 2 types of regional anesthesia. Regional anesthesia may be given as a "peripheral nerve block." Your doctor may give you this for a procedure on a hand, arm, leg, or foot. It blocks feeling in the nerves to these areas.

Another type of regional anesthesia is an epidural or a spinal anesthetic. This blocks pain in your abdomen or lower body, including the pelvis, rectum, and legs.


Sedation is medicine that makes you feel relaxed and sleepy. You may take a a pill or liquid by mouth, or get it through a vein (IV). Your doctor might give you sedation along with local or regional anesthesia. It can make you more comfortable and reduce pain.

There are 3 levels of sedation.

Minimal sedation

This type of sedation makes you relaxed. If you feel anxious or nervous, it helps you feel comfortable during a test or procedure. You are awake during the procedure and you can talk.

Moderate sedation

This type of sedation reduces pain and makes you less aware of things around you. Another name is "conscious sedation." You might be able to talk and respond to questions, or you might doze off. You might have this type of sedation for a minor surgery, along with local or regional anesthetic. You might not remember the procedure afterwards.

Deep sedation

You are not aware of the procedure and cannot usually talk or answer questions. You may receive pain medication to reduce any discomfort. You might also have drugs that affect your memory, so you do not remember the procedure. Doctors might give you oxygen or a breathing tube to help you keep breathing well during deep sedation.

General anesthesia

You are unconscious during general anesthesia. It is similar to being asleep, but you only wake up when the anesthesia medicines wear off. Or doctors might give you medicines to wake you. Doctors usually use general anesthesia for major procedures like surgery.

Who gives anesthesia?

Your anesthesia team might include several people.

An anesthesiologist

This is a doctor who specializes in giving anesthesia and caring for people who have it. This person will lead your anesthesia team.

A surgeon

In some cases, the doctor performing your surgery may administer the anesthesia themselves. This is especially true if it is topical anesthesia.

A certified registered nurse anesthetist

This is a registered nurse with specialized training in anesthesia. You might see the letters CRNA after their name.

Anesthesia assistant

This is a health care professional with a college degree and additional training in anesthesia care. They specialize in taking care of patients during and after anesthesia.

Getting ready for anesthesia

Your anesthesiologist may meet with you before you have general anesthesia. You will also answer some questions. They might be a printed list, or someone might ask you the questions. These may include about:

  • Your health, now and in the past.

  • What medicines, vitamins, and herbal supplements you take, including prescription and over-the-counter products.

  • Any allergies, including to foods, medicines, and items like latex.

  • Any anesthesia you had before, and your experience.

  • Drug, alcohol, and tobacco use.

It is important to answer these questions honestly and correctly. The information helps them give you anesthesia as safely as possible.

You may also need blood tests or other examinations before general anesthesia. This helps make your experience with anesthesia safer.

Before general anesthesia

You will probably need to go without eating for at least 6 hours before general anesthesia. Do not eat or drink anything unless your doctor tells you it is OK. You may be able to drink clear liquids until a certain time.

You might need to stop taking your regular medicines before general anesthesia. Some medicines can affect the anesthesia or your procedure. But ask your doctor before you stop taking any medicines.

Tell your doctor if you have any loose teeth or dental bridges. Some types of anesthesia may involve movement around your mouth, such as putting in a tube. Your team wants to protect your teeth.

What happens during general anesthesia?

You will receive general anesthesia in 1 of these ways:

  • Through an IV line placed in a vein in your arm

  • Through a face mask or tube in your windpipe. This helps you breathe in the medicine

  • Both of these

You will probably feel the effects of anesthesia in less than 1 minute.

Your health care team will place devices on your body before you have anesthesia. For example, you might have a small clip on your finger to measure the amount of oxygen in your blood. The devices help your team keep track of your body temperature, blood pressure, heart rate and breathing. The team will make sure these are all OK during the procedure. They will also keep track of your anesthesia level to make sure you do not wake up until the right time.

The anesthesiologist will stop the anesthesia when your procedure is over. They might also give you medicines to help you wake up. Next, you will go to a recovery area. Specially trained nurses will take care of you as you wake up completely.

Possible side effects of anesthesia

Anesthesia is safe for most people. Side effects may include:

  • Grogginess, sleepiness, or confusion

  • Nausea or vomiting

  • Chills

  • Dry mouth or sore throat. You may have this if your team put in a tube to help you breathe during the procedure.

These side effects are temporary. Your health care team will help you manage them.

Serious injury and death are rare side effects of anesthesia. The risks may be higher for older adults, especially people with severe heart or lung disease.

Anesthesia awareness is another rare side effect. This means a person briefly wakes up during the procedure. It happens in 1 or 2 out of every 1,000 people.

Risk factors for anesthesia awareness are:

  • Emergency surgery

  • Using certain medicines for a long time, including tranquilizers, opioids, and medicines called anti-convulsants.

  • Heart and blood vessel problems

  • Daily alcohol use

  • Smoking now or in the past

Recovering from general anesthesia

It takes some time to get back to normal after general anesthesia. Avoid these activities for at least 24 hours after waking up.

  • Driving a car

  • Operating heavy machinery

  • Making important decisions

Your reaction speed and judgment may be slow or different for a while after anesthesia.

If your do not think you are recovering well from anesthesia, contact your health care team right away.

Ask your health care team when to start taking your regular medicines again. Also ask if you should wait to have certain foods or drinks. You may have trouble digesting heavy foods. You may start by drinking liquids and then eating light foods until you feel normal again. Examples of light foods include:

  • Broth or soup

  • Tea or black coffee

  • Yogurt

  • Gelatin

  • Toast, crackers, or plain rice

Questions to ask your health care team

You may want to ask these questions before anesthesia:

  • Do I have a choice about the type of anesthesia I have?

  • What are the risks and complications of each type of anesthesia?

  • How can I prevent or lower risks and complications?

  • Do I need any tests before having anesthesia?

  • May my family come to the operating room with me?

  • Can I bring any electronic devices or headphones to the operating room?

  • What care will I have before, during, and after my procedure?

Related Resources

What is Cancer Surgery?

What to Expect When Having Surgery

Side Effects of Surgery

More Information

American Society of Anesthesiologists: Anesthesia 101

MedlinePlus: Anesthesia