Novartis's own studies show that it is only 5 percent to 10 percent more effective than placebos at resolving the symptoms of constipation-related irritable bowel syndrome in women.

'If you feel constantly bloated for more than a couple of weeks and that feeling doesn't disappear after you've been to the loo, then book an appointment to see your GP.

Diarrhoea is a common symptom of irritable bowel syndrome, which affects an estimated four million women in Britain.