The exact cause of IBS-D is still unknown. We do know that it’s more common in women and people under 50. If someone in your family has IBS, your chances of getting it are higher. Some other causes include:
- Sensitive colon: Your colon may react too strongly to certain triggers like stress, bacteria, or foods.
- Brain signals: Your brain might send too many signals to your colon, causing it to squeeze too hard.