When should I worry about diarrhoea?

It may not be dinner party conversation, but most of us have tummy trouble at some point. Diarrhoea, vomiting and colicky tummy pain together often signifies food poisoning or a bug, but if it goes on, you need it looked into. Short term diarrhoea due to a tummy bug is common, but see your doctor if it persists for over a week. Likewise, always see your doctor if you've recently travelled somewhere exotic (outside Western Europe, the USA or Australasia), if you have blood in the diarrhoea or vomit or if you have other long term health conditions.

What 'chronic' and 'diarrhoea' means in medicine

My patients often use the word 'chronic' when they mean 'dreadful' ('I've been up all night with chronic stomach ache') but in medical terms it's used to mean long term. But how long 'long term' is is a moveable feast.

As far as diarrhoea is concerned, some doctors say it's chronic if it's gone on more than two weeks, and some four weeks. One study suggested that one in 20 people get diarrhoea lasting at least four weeks in any year. Of course, the next question is what doctors mean by 'diarrhoea'. Officially opening your bowels more than three times a day, with loose or liquid poos, is diarrhoea - but with some tummy bugs and other conditions, going a dozen times a day is common.

Some common causes of diarrhoea

Irritable bowel syndrome, or IBS, commonly causes diarrhoea or constipation, or a mix of the two along with tummy pain (often eased by opening your bowels or passing wind) and bloating. However, it rarely starts over the age of 40 and you should never assume this is the cause. If it is diagnosed by your doctor, diet and lifestyle changes (including regular exercise and managing stress), along with tablets, can help. Doctors used to recommend a high-fibre diet, but it's now recognised that this can make diarrhoea worse.

Coeliac disease is an autoimmune disease - where your own immune system attacks part of your body, in this case the small bowel. It affects about one in 100 people, and while it can be diagnosed at any age, the commonest time to be diagnosed is in your 50s or 60s. Your body reacts to gluten, found mostly in wheat, barley and rye. Along with diarrhoea bloating and wind, coeliac can stop your absorbing vitamins and nutrients and can lead to anaemia and tiredness. Weight loss and mouth ulcers sometimes happen too. These days, you can usually be diagnosed with a blood test, although you may need a biopsy of your small bowel too. Treatment involves avoiding all food containing gluten for life - fortunately there are lots of options in the shops.

Inflammatory bowel disease includes ulcerative colitis, which affects your colon (large bowel) and Crohn's disease, which can affect your large and small bowel. (link to Both start most commonly in teenagers and young adults, but there is another 'peak' in new cases in people in their 50s-70s. Along with chronic diarrhoea, you may also suffer from bleeding from the bottom, colicky tummy pain, needing to rush to the loo, fever, weight loss and tiredness. If your doctor suspects either of these conditions, they will want to do blood tests and probably a sample of your poo to check for 'faecal calprotectin' - if this is positive you will need to be referred to a hospital specialist.

An overactive thyroid gland makes your body tick over more quickly. Symptoms include diarrhoea, weight loss, feeling hot and trembling.

The range of medicines that can cause diarrhoea is endless. Common culprits include metformin (for type 2 diabetes), antibiotics, laxatives (amazing how often patients don't make the connection!), medicines for indigestion, anti-inflammatory painkillers and chemotherapy. If you've recently started a new medicine, speak to your pharmacist about whether this might be the cause. Don't stop medicines without medical advice, though - side effects like diarrhoea often settle within a few weeks and your doctor can advise on whether an alternative might be better.

It's important to remember that in most cases, diarrhoea doesn't mean colon cancer. However, it's something your doctor may consider, especially if you're over 50 or also have unexplained bleeding from your bottom, or have lost weight or been off your food. If you have bleeding from your back passage, always see your doctor. It's usually down to piles or another non-sinister cause, but better safe than sorry.

With thanks to 'My Weekly' magazine where this article was originally published.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.