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As with any type of surgery, a gastrectomy carries a risk of complications. Problems can also occur due to changes in the way you digest food.

As with any type of surgery, a gastrectomy carries a risk of complications. Problems can also occur because of changes in the way you digest food.


Gastrectomies to treat stomach cancer have a higher risk of complications, because most people who have this type of surgery are elderly and often in poor health.

Complications can also occur after a gastrectomy to treat oesophageal cancer. The oesophagus is the tube connecting your throat to your stomach.

Possible complications of a gastrectomy include:

  • wound infection
  • leaking from where the stomach has been closed or reattached to the small intestine
  • stricture where stomach acid leaks up into your oesophagus and over time causes scarring, leading to the oesophagus becoming narrow and constricted
  • chest infection
  • internal bleeding
  • blockage of the small intestine (small bowel)

An infection can usually be treated with antibiotics, but some other complications will require further surgery. Before your operation, ask your surgeon to explain the possible risks and how likely they are to affect you.

It's estimated that around 2 in 100 people who have a gastrectomy for cancer die from complications.


Possible complications of a gastrectomy for obesity include:

  • nausea and vomiting which usually get better over time
  • internal bleeding which can lead to blood clots forming
  • leaking from where the stomach has been closed
  • acid reflux where stomach acid leaks back up into the oesophagus
  • infection

It may be possible to treat some complications with medication, but others may need further surgery. Before your operation, ask your surgeon to explain the possible risks and how likely they are to affect you.

The risk of death from a gastrectomy for obesity is very low, estimated as less than 1 in 100.

Vitamin deficiency

One function of your stomach is to absorb vitamins, particularly vitamins B12, C and D, from the food you eat.

If your entire stomach has been removed, you may not get all the vitamins your body needs from your diet. This may lead to certain health conditions, such as:


The body requires vitamin B12 to make healthy blood cells. Without enough healthy blood cells, you could develop symptoms of anaemia, such as tiredness and breathlessness.

Increased vulnerability to infection

Vitamin C helps to strengthen your immune system (the body's natural defence against infection and illness). If you don't have enough vitamin C in your diet, you may develop frequent infections. Wounds or burns will also take longer to heal.

Brittle bones and weakened muscles

Your body needs vitamin D to keep both your bones and muscles strong and healthy. If there isn't enough vitamin D in your diet, you could develop pain and weakness in your bones (osteoporosis) and muscles.

Changing your diet may help to compensate for your stomach's inability to absorb vitamins. However, even after changing your diet, you may need vitamin supplements. The healthcare professionals treating you can advise on this.

Read about recovering from a gastrectomy for more information on diet and supplements.

Weight loss

Immediately after surgery, you may find that eating even a small meal makes you feel uncomfortably full. This could lead to weight loss. Losing weight may be desirable if you've had a gastrectomy because you're obese, but it can be a health risk if you've been treated for cancer.

Some people who have a gastrectomy regain weight once they have adjusted to the effects of surgery and have changed their diet. However, if you continue to lose weight, see a dietitian (a healthcare professional who specialises in nutrition). A dietitian can give you advice on how to increase your weight without upsetting your digestive system.

Dumping syndrome

Dumping syndrome is a set of symptoms that can affect people after a gastrectomy. It's caused when particularly sugary or starchy food moves suddenly into your small intestine.

Before a gastrectomy, your stomach digested most of the sugar and starch. However, after surgery your stomach can no longer do this, so your small intestine has to draw in water from the rest of your body to help break down the food.

The amount of water that enters your small intestine can be as much as 1.5 litres (3 pints). Much of the extra water is taken from your blood, which means you will experience a sudden fall in blood pressure.

The drop in blood pressure can cause symptoms such as:

  • faintness
  • sweating
  • palpitations
  • a need to lie down

The extra water in your small intestine will cause symptoms such as:

  • bloating
  • rumbling stomach
  • nausea
  • indigestion
  • diarrhoea

If you have dumping syndrome, resting for 20-45 minutes after eating a meal may help. To ease the symptoms of dumping syndrome:

  • eat slowly
  • avoid sugary foods such as cakes, chocolate and sweets
  • slowly add more fibre to your diet
  • avoid soup and other liquid foods
  • eat smaller, more frequent meals

Seek advice from your hospital team or dietitian if you have symptoms of dumping syndrome. For most people, the symptoms improve over time.

Morning vomiting

After a partial gastrectomy, a small number of people may experience morning vomiting.

Vomiting occurs when bile (a fluid used by the digestive system to break down fats) and digestive juices build up in your duodenum overnight, before spilling back into what remains of your stomach. The duodenum is the first part of your small intestine.

Due to its reduced size, your stomach is likely to feel uncomfortably full and this will trigger a vomiting reflex to get rid of the excess fluids and bile.

Taking indigestion medication, such as aluminium hydroxide, may help to reduce the symptoms of morning vomiting. See your GP if your symptoms are particularly troublesome.


During a gastrectomy, it's sometimes necessary to cut a nerve called the vagus nerve. The vagus nerve helps to control the movement of food through your digestive system.

Although the vagus nerve will heal after surgery, a small number of people will experience bouts of severe diarrhoea. However, they usually only occur now and again, and should pass within a day or so.

Taking diarrhoea medication, such as loperamide, in the morning may help to reduce your symptoms.

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