Can you drink water up until surgery?

Staying hydrated is important before surgery, but knowing when to stop drinking water can be confusing. Many people wonder if they can drink water right up until the time they go into surgery or if they need to stop drinking hours beforehand.

Quick Answers:

– It’s generally recommended to stop drinking clear liquids, including water, at least 2 hours before surgery. This is to prevent aspiration of stomach contents during anesthesia.

– Some surgeries, like those involving the digestive tract, may require longer fasts from all food and drink, up to 8-12 hours pre-op.

– For minor procedures like endoscopies, you may be allowed clear liquids up to 1 hour before.

– Always follow your provider’s specific instructions on fasting times before surgery.

– Taking small sips to take medication is usually permitted up until surgery time.

– After midnight fasting from all solids is typical, while clear liquids may be allowed up to 2 hours pre-op.

– Staying hydrated in the days leading up to surgery can help prevent issues like dizziness or low blood pressure.

Why stop drinking water before surgery?

There are a few important reasons to stop oral intake of fluids in the hours before surgery:

Prevent aspiration:

When you undergo general anesthesia for surgery, you lose your gag reflexes and ability to cough. If there is fluid or food in your stomach, it could potentially be aspirated into your lungs while you are unconscious. This aspiration can cause serious pneumonia, so surgeons want your stomach as empty as possible prior to anesthesia. Stopping oral intake for 2 hours pre-op significantly reduces your risk of this dangerous complication.

Allow for accurate testing of gastric fluid:

Testing the pH of your stomach secretions can help assess risk of aspiration. If you have recently ingested fluids, it can alter results and hide potential problems. Holding oral intake allows for more precise testing.

Facilitate visualization:

For surgeries involving the abdomen or digestive organs, an empty stomach allows for better visualization and access during the operation. Any fluid or food material can obstruct the operative field.

Reduce risk of side effects:

Drinking too close to surgery may increase risk of side effects like regurgitation of stomach contents under anesthesia or postoperative nausea and vomiting. Allowing time for your stomach to fully empty can help minimize these undesirable effects.

Typical fasting instructions before surgery

Here are the standard recommendations for fasting before anesthesia:

For solids:

– Stop intake of all solid foods and non-clear liquids after midnight the night before surgery.

– No milk, juice with pulp, coffee, or other opaque beverages.

For clear liquids:

– Stop clear liquids 2 hours before scheduled surgery time.

– Clear liquids include water, black coffee/tea, clear juice without pulp, sports drinks, gelatin.

For medications:

– Take scheduled morning medications with only small sips of water up to 2 hours pre-op.

– Consult with your surgeon about taking any medications the morning of surgery.

Time Before Surgery Allowed
After midnight No solids, non-clear liquids
2 hours before No clear liquids
Up until 2 hours before Clear liquids

These are general guidelines that may vary based on your specific surgery, medical history, and instructions from your surgical team. Some procedures require longer pre-op fasting, while others may be more flexible if anesthesia risk is low.

When you need to fast longer

While 2 hours is typical, some situations call for longer fasting times from both solids and liquids:

Bowel surgery:

For procedures involving the stomach, intestines, or colon, you will likely be told to stop clear fluids 8-12 hours beforehand and avoid eating for 12 hours or more before surgery. This ensures the bowel is free of contents.

Sedation dentistry:

Oral surgeons often require fasting from both solids and clear fluids for 6-8 hours pre-op since you are not intubated and at higher aspiration risk.


Patients with diabetes may be told to hold solids for 8 hours and liquids for 4-6 hours pre-op to help control blood sugar.

Reflux or delayed gastric emptying:

Those at risk of reflux or with conditions like gastroparesis may need longer fasts from all solids and liquids.

Infants and young children:

Pediatric patients are more prone to aspiration so may have prolonged fasting instructions before surgery.

Talk to your doctor about the specific fasting regimen you should follow based on your health history and type of procedure. When in doubt, follow the longer time period to ensure safety.

When you may be able to drink closer to surgery

While 2 hour fasting from clear liquids is the standard, some minor procedures allow more flexibility:

Cataract surgery:

Since this is a surface eye surgery, restrictions are more relaxed. Clear liquids may be allowed up to 1 hour before.


For routine upper endoscopy or colonoscopy, clear liquids are often permitted until 1 hour pre-op to help prep the bowel.

Superficial skin surgery:

Procedures involving only local numbing may let you drink small amounts up until surgery time.

Cardiac catheterization:

You may be allowed sips of water to take blood pressure medications right before this type of procedure.

Talk to your surgeon about appropriate fasting instructions for your specific situation. While they may allow limited fluids closer to surgery time, stopping 2 hours before is the standard protocol.

Can you drink water right up until surgery?

Drinking water right before surgery is generally not a good idea. While plain water may seem harmless:

– Even water sits in the stomach and increases aspiration risk with anesthesia.

– It can alter stomach pH testing prior to surgery.

– Water intake too close to surgery time may lead to unexpected delays so the stomach has time to empty.

– Taking sips with medications may be allowed, but quickly finishing a glass or bottle of water right before heading into the OR is not recommended.

Follow your providers exact instructions, but expect to be cut off from plain water at least 2 hours before your scheduled surgery time.

Staying hydrated before surgery

While oral intake stops 2-12 hours beforehand, proper hydration in the days leading up to surgery is important:

– Drink plenty of clear fluids like water and juices in the 24+ hours prior.

– Avoid alcohol and limit caffeine which can be dehydrating.

– Consider supplemental IV fluids pre-op if you have reduced intake due to fasting or bowel prep.

– Discuss with your doctor if you have history of dehydration, dizziness, or low blood pressure.

– Monitor your urine color – pale yellow means you are well hydrated.

Being well hydrated before surgery can help:

– Prevent dizziness, fainting, or low blood pressure.

– Maintain good circulatory volume status during surgery.

– Improve recovery and healing.

– Allow accurate monitoring of fluid status intraoperatively.

– Reduce risk of kidney injury or pre-renal failure.

Careful prep along with IV fluids given during the procedure help make up for deficits from pre-op fasting.


Pre-operative fasting is important to minimize risks and improve surgical outcomes, but proper hydration is also key. Follow your provider’s recommendations, stopping all solids 8-12 hours before procedures and clear fluids 1-2 hours beforehand. Allow enough time for your stomach to completely empty prior to anesthesia, but don’t let fasting lead to dehydration. With the right preparation, you can safely undergo surgery and get back to drinking water as you recover.

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