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Physical problems related to purging

Purging refers to the ways people with an eating disorder try to get rid of food so they don't gain weight. Some people vomit, or exercise excessively (more than is needed to keep fit and healthy), or restrict their food. Others take various drugs which they believe will help them lose weight or look thinner.


People with bulimia often self-induce vomiting to try to undo the effects of a binge, or even after eating a small amount of food. After a while, some people find they do not have to self-induce vomiting any more because they vomit automatically after eating. They then have the opposite problem of not being able to keep any food down.

Repeated vomiting causes many physical problems. Frequent exposure to stomach acid leads to severe tooth decay. The oesophagus and stomach can rupture if someone vomits large amounts. They can get scrapes on their knuckles from sticking their fingers down their throat. Electrolyte imbalances, malnutrition, and an inability to feel hunger and fullness can follow.


Purgatives are drugs or other substances which make you vomit (emetics), or urinate (diuretics), or cause diarrhoea (laxatives).


Diuretics make you urinate, or pee, more. Most diuretics are tablets, either prescribed by a doctor, or available over the counter. Some other substances such as caffeine also act like diuretics. Around one-third of women with eating disorders have used diuretics at some time, and about 1% use them daily. They often use them to stop the weight gain that happens with pre-menstrual water retention.

Diuretics have no effect at all on calories or body fat. They just make you lose water, which changes in the balance of electrolytes in the body. Over time, this can lead to serious medical problems, including heart problems. Too much caffeine can lead to restlessness, insomnia, irritability, nervousness, and gastrointestinal problems, as well as increased urination.

Often if you use a diuretic regularly, you may need more of it to get the same effect – you develop a tolerance for it. And you may have problems with long-term water retention when you do stop taking diuretics.


Emetics are substances that make you vomit. Around 30% of women with eating disorders have used emetics at some time, to make vomiting easier.

Some emetics take a long time to clear from the body, so that they build up.This is especially true if you have been taking emetics regularly, since you can become tolerant (you need more of the drug to make you vomit). This is extremely dangerous, as these drugs are highly toxic above certain doses.

As well as nausea and vomiting, emetics can cause medical complications such as gastrointestinal problems (for example, bloody diarrhoea), muscle weakness, a rapid heart rate, chest pain, shortness of breath, low blood pressure, irregular heartbeat, and cardiac arrest (heart failure). Blood pressure monitor


Laxatives are substances that get rid of the food in the bowel by increasing the volume of stools (poos), or speeding up the passage of food through the gut. Some laxatives act by increasing muscle activity which moves food through the intestine more quickly. Others coat the stool with oil, or soften it, or increase the amount of water or fibre in the stool so that it moves more quickly.

Many women with eating disorders (between 38% and 75%) use laxatives to try to counteract the effects of bingeing and to lose weight. They believe this will get rid of the food they eat, but it doesn't. One study found that even though laxatives cause a large amount of diarrhoea, laxatives decrease the number of calories digested by only about 10%. This is because they make you lose water and electrolytes only, not calories. They also mainly affect the emptying of the large intestine, after the small intestine has already absorbed the calories from the food.

Regularly using laxatives can lead to medical problems including recurrent diarrhoea, weakness, abdominal pain, nausea, vomiting, dehydration, electrolyte imbalance (in particular, low levels of potassium), finger clubbing, skin problems, and heart problems. Many of these problems are caused by chronic dehydration because you are losing too much water. Dehydration has many side effects including dizziness and fainting, chronic fatigue, confusion, increased body temperature, kidney failure and in severe cases, death.

Using laxatives regularly may also mean you need greater amounts to get the same effect (you develop tolerance).

Sometimes people who abuse laxatives for too long can no longer do poos without them, because laxatives also affect the nerves that normally make the muscles of the bowel contract. These people need specialised retraining to help their muscles function again.

There are also side effects that happen when you try to stop using laxatives. These include water retention, constipation, increased anxiety (feeling edgy, irritable, tense, angry), and urges, or cravings, to take laxatives. Although these side effects can be uncomfortable and distressing at first, within a short time (usually about two weeks), your body becomes used to not taking laxatives and the side effects will start to go away.

Appetite suppressants (diet pills)

People with eating disorders often take appetite suppressants (including diet pills, and some other medicines) to dull their appetite, so they feel like eating less and lose weight.

These appetite suppressants may be prescription drugs, over-the-counter pills or medicines, or common substances such as caffeine. A quarter to half of women with eating disorders have used appetite suppressants at some time, but there is very little evidence that appetite suppressants actually result in weight loss. However, some appetite suppressants can cause serious medical problems, including increases in blood pressure, seizures, bleeding in the brain, cardiac irregularities, respiratory problems, and psychosis. These effects may be greater when some appetite suppressants are taken with other substances, including caffeine.

Written by the South Island Eating Disorders Service. Adapted by HealthInfo clinical advisers. September 2013


See also:

What are the health and social risks of an eating disorder?

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