Every operation is different, and whether or not you are allowed to eat or drink beforehand, and what you can have, will depend on the type of operation being carried out.
Before you have your operation, the health professionals treating you will tell you whether you can eat or drink and, if eating and drinking is permitted, what foods and liquids you can have.
Before having an operation, it's likely that you'll be given either a local or a general anaesthetic. A local anaesthetic numbs the area being treated, so that you don't feel any pain. A general anaesthetic makes you unconscious so that you can't feel anything, and you aren't aware of what's going on during the procedure.
Usually, before having a general anaesthetic, you won't be allowed anything to eat or drink. This is because when you're under anaesthetic, your body's reflexes are temporarily stopped.
If your stomach has food and drink in it, there's a risk of vomiting, or regurgitation (bringing up food into your throat). If this happens, the regurgitated food could spill into your lungs and affect your breathing, as well as causing damage to your lungs.
The amount of time that you have to fast for (go without food or drink) before you have your operation will depend on the procedure that you are having. However, it is usually six to eight hours for food, and two hours for fluids.
The use of chewing gum, including nicotine gum, should be avoided during this fasting period.
You may be told to avoid certain types of fluids, such as milk, or white tea and coffee, as they have proteins and fats in them which could damage your lungs. Clear fluids, such as water, black tea or coffee, or processed fruit juices, are usually recommended.
Infants can be given breastmilk up to four hours before an operation. After that time only clear fluids should be given.
If you have a medical condition, such as diabetes, that means you need to eat and drink regularly, you should tell one of the healthcare professionals treating you prior to having an operation. You should also let them know if you are taking any medication.
If you are having a local anaesthetic, you should be allowed to eat and drink as normal before you have the procedure. An exception to this is maybe if you are having a procedure that involves your digestive system or bladder.