The exact cause of IBS is not known. However, most experts agree that there are factors that may trigger, or worsen symptoms. These include:
Diet 
- Large meals, or food containing a large amount of fat can upset the bowel.
- Find out more about common foods that can trigger IBS symptoms: Balanced diet.
Stress and anxiety
- Your bowel will respond to stress and anxiety, which in the IBS sufferer often results in constipation or diarrhoea.
- Try some anti-stress techniques to reduce the impact of stress and calm symptoms: Anti-stress exercises.
Female hormones
- Experts have found that symptoms can be worse when a woman has her period, which suggests hormones play a role in the condition.
Medicines
- Certain medicines such as iron tablets, some painkillers and antibiotics, can upset the bowel and produce symptoms of IBS.







