Ascites is a build-up of fluid in the lining of the tummy (abdomen). It can be caused by cancer. Find out about symptoms and how to treat ascites.

What is ascites?

Inside the tummy (abdomen) there is a membrane called the peritoneum. It has two layers. One of the layers lines the tummy wall. The other layer covers the organs inside the tummy.

Side view of the tummy (abdomen) showing the peritoneum

The peritoneum makes ascitic fluid, which acts as a lubricant between the two layers. This allows the organs to glide smoothly over each another. Sometimes this fluid can build up between the two layers. This is called ascites.

What causes ascites?

Ascites can be a symptom of many type of cancer. It can also be caused by some other conditions, such as advanced liver disease and heart failure.

Ascites may develop when:

  • cancer cells irritate the lining of the tummy, causing it to make too much fluid
  • lymph nodes in the tummy become blocked and the fluid cannot drain properly
  • cancer that has spread to the liver raises the pressure in nearby blood vessels, which forces fluid out
  • the liver is damaged and cannot make enough blood proteins, so fluid leaks out of the veins into the tummy.

Symptoms of ascites

The main symptom of ascites is bloating and a swollen tummy.

Other symptoms include:

  • discomfort or pain in the tummy
  • feeling sick (nausea)
  • loss of appetite
  • indigestion
  • tiredness and weakness (fatigue)
  • constipation
  • needing to pee (pass urine) more often
  • breathlessness
  • difficulty sitting comfortably and moving around.

Managing ascites

Ascites is often managed by draining the fluid. Your doctor may also suggest some tablets to help your body get rid of the extra fluid. If cancer is causing the ascites, treating the cancer may help.

Draining fluid from the tummy (ascitic drainage)

Removing the excess fluid from the tummy is a common and effective treatment for ascites. It is done by putting a tube (catheter) into the tummy to drain the fluid. This relieves the symptoms and helps you feel more comfortable.

You often have this treatment as a day patient. You will usually be at the hospital for at least 6 hours. You may want to bring something to help pass the time, such as something to read, watch or listen to. You might need to stay in hospital overnight.

A specially trained doctor or nurse does the treatment. You lie down on a bed, or in a reclining chair. The doctor or nurse cleans the skin of the tummy. Then they inject some local anaesthetic into the area to numb it.

They make a very small cut in the skin of the tummy and insert the tube. They might use an ultrasound scan to help them position it. The fluid drains out of the tummy and collects in a drainage bag. The tube is covered with a dressing. Sometimes the doctor or nurse uses a couple of stitches to hold it in place.

If you have any pain or discomfort, tell your doctor or nurse. You can have painkillers if you need them.

Fluid being drained from the tummy (ascitic drainage)

The fluid is usually drained over a few hours, but this depends on:

  • the amount of fluid that needs to be drained
  • what is right for you – for example, if you have low blood pressure, fluid may be drained more slowly.

After the tube is removed, a small amount of fluid may leak until the hole heals. You will have a dressing or drainage bag over the area until this stops. Your doctor and nurse can tell you more about this.

The fluid may build up again. If this happens, you may need to have it drained more than once. If your doctor thinks you may need repeated ascitic drainage, they may suggest putting in a catheter that will stay in place long term (see below).

Possible problems with ascitic drainage

Most people do not have any serious problems from having an ascitic drain. As the fluid drains, it can cause some people’s blood pressure to drop and their heart rate to increase. Your nurse will check your blood pressure, heart rate (pulse) and breathing regularly so they can treat this problem if it happens.

Sometimes the catheter can become blocked, which stops the fluid from draining. Changing your position or sitting upright may help if this happens.

Other problems

  • You might need to have a catheter in more than one place if there is ascitic fluid in different places in the tummy.
  • There is a small risk of bleeding when the catheter is put in. Any bleeding usually stops on its own without treatment.
  • There is a small risk of hitting the bowel when putting in the catheter. This rarely happens. But it is a serious problem which would need treating with antibiotics and resting the bowel. Your doctor or nurse can tell you more about this.
  • The catheter site can become infected. This is not common. Your nurse will check your catheter site regularly for signs of infection, such as redness or pus. They will also check your temperature regularly, as a high temperature can be a sign of infection. If you get an infection, they will give you antibiotics.
  • Fluid may leak around the catheter. The dressing around the catheter will be changed regularly. Any leaking usually stops after the fluid has been drained.

Long-term drainage catheter

This can help to manage ascites that builds up again quickly after drainage. It is similar to an ascitic catheter, but it stays in place after the fluid has drained. When the catheter is not being used, it is closed and covered by a dressing.

When the fluid builds up, a drainage bottle or bag is attached to the catheter. The catheter is then opened and drains fluid from your tummy. Your doctor or nurse can tell you more about this and show you how to look after the catheter.

Placing an internal tube (shunt)

Some people have a tube, called a shunt, put into their tummy. You need to be quite fit to have this procedure. It drains the fluid directly into a large vein. Doctors call this a peritoneo-venous shunt.

Peritoneo-venous shunt

You will be given either a sedative (which makes you drowsy) or a general anaesthetic when the doctor puts the shunt in.

One end of the shunt goes into the fluid in the tummy. The other end goes into a vein in the neck. A valve in the shunt means the fluid can only flow in one direction – from the tummy into the vein in the neck.

You will need to stay in hospital for a short time while the hospital staff check the shunt is working properly. The shunt stays in permanently. Your doctor and nurse can give you more information about this.

Other ways to manage ascites

Treating the cancer

Cancer treatments such as chemotherapy can help to reduce the number of cancer cells. This can sometimes improve ascites.

Drug treatments

Your doctor may give you a water tablet (diuretic), such as spironolactone. This may help the body get rid of excess fluid as urine (pee). Your doctor or nurse may also advise you to reduce the amount of salt you have in your diet.

Taking a water tablet can help slow down the build-up of the ascitic fluid. It usually makes you want to pass urine more often. You may have blood tests to check how well your kidneys are working during this treatment.

Your feelings

If you have ascites, the way you think and feel about your body (body image) may change. You may find it helpful to:

About our information


  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Dr Paul Ross, Consultant Medical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.