Diarrhoea is common among people with HIV. It can be a side-effect of anti-HIV drugs as well as some other medicines, such as antibiotics. Diarrhoea can also be caused by infections. If you have a weak immune system you may be more likely to get these infections and for them to be serious. HIV itself can also cause diarrhoea because of its effect on the gut.

Diarrhoea can take the form of a semi-loose to completely liquid stool, and may result in having to go to the toilet more frequently and urgently. It is common for diarrhoea to be accompanied by stomach pains, bloating, nausea, vomiting, fever and loss of appetite.

Diarrhoea can be caused by some anti-HIV drugs. With some drugs, diarrhoea goes away after the first few weeks or months of treatment, however for some people it becomes a permanent feature of living with the drug.

The severity of diarrhoea also varies. Severe diarrhoea, involving several trips to the toilet each day, large, uncontrollable liquid bowel movements, and feelings of weakness and dizziness as a result of the loss of fluids and electrolytes is experienced by about a quarter of people starting treatment with nelfinavir (Viracept), which is now very rarely used and by a lower proportion of people starting saquinavir (Invirase), fosamprenavir (Telzir) and lopinavir/ritonavir (Kaletra). These drugs are in a group (or drug class) called protease inhibitors. Less serious problems have been experienced by people taking other anti-HIV drugs in this class and in other classes. 

Changes in diet have little effect on drug-related diarrhoea. However a variety of treatments are available to try to control diarrhoea caused by drugs. These include:

• Imodium (loperamide). This is available on prescription from your doctor or can be bought over the counter from chemists. Stronger anti-diarrhoea drugs can be prescribed by your doctor.
• Oat bran tablets have also been shown to be effective. They work by absorbing fluid, making stools larger and slowing the movement of stools through the intestines.

It is important that you continue to eat and drink even if you have diarrhoea which is caused by your medication. You should not stop taking your medication because it causes diarrhoea. Instead, you should discuss any problems with your doctor, who may be able to recommend treatments for the diarrhoea or, if necessary, a change your HIV treatment.

Diarrhoea is very common among people with HIV, particularly those with a low CD4 count. Often no specific cause can be found, and in cases of mild diarrhoea the cause might be HIV. Another common cause is irritable bowel syndrome, when diarrhoea often alternates with constipation and is associated with bloating and wind. Rather than being caused by an infection it is likely that lifestyle issues, such as stress, are to blame.

Diarrhoea can also be caused by bacterial infections, parasites and viruses, so if diarrhoea persists it is important to investigate the cause.

Usually diarrhoea will settle down after a few days. If it lasts longer, it is important to see your doctor so the cause can be investigated and you can receive the right treatment.

As diarrhoea may result in losing essential salts and water from the body, it is important to drink plenty of fluids or special rehydration drinks. Eating foods like bananas, potatoes, chicken and fish will help you replace potassium, levels of which are commonly lowered in people with severe diarrhoea. Pulses, oats, bananas, apples and pears have also been shown to be effective against diarrhoea. Charcoal tablets may also be helpful. For general advice on nutrition, you may find NAM's Nutrition booklet helpful.

Try to avoid coffee, raw vegetables and spicy food as they can make diarrhoea worse, and may also be triggers for nausea, which is often combined with diarrhoea. In many cases, avoiding foods which are high in fat, or milk may help alleviate the symptoms of diarrhoea.

Increasing or decreasing the fibre content of your diet may help if you have irritable bowel syndrome, as might Colofac.

You might find it useful to speak to a specialist HIV dietician, who can provide you with advice on suitable dietary changes, how to avoid losing weight and how to get adequate nutrition when you have diarrhoea.

Diarrhoea can also cause soreness around the anus. Over-the-counter remedies for piles may prove soothing.