What Is IBS with Diarrhea?

IBS-D is a subgroup of Irritable Bowel Syndrome defined as IBS with diarrhea, where loose stools and sudden urges to visit the toilet are likely.

IBS-D is the most common subgroup of Irritable Bowel Syndrome (IBS,) with almost 31.5% of cases worldwide1!

Contrary to constipation symptoms, people with IBS-D do not only experience looser stools, but also have an abrupt impulse to frequently use the toilet. Unfortunately, symptoms can vary and normally persist for many years.

Signs and Symptoms of IBS-D

  • Mucus and blood in stools
  • Lower abdominal pain
  • Watery stools
  • Bloating
  • Rectal pain
  • Nausea
  • Heart-burn
  • Indigestion2

What Causes IBS-D?

Similar to IBS-C, there are no clear answers to what the underlying causes of IBS-D are. However, several plausible factors can potentially explain IBS-D. One popular theory revolves around gut health. Some studies suggest that people with a prior gut infection are more susceptible to IBS-D.

Changes in certain gut microbes are noted as potential indicators to ISB-D3:

  • Lactobacillus spp. – The probiotic option
  • Proteobacteria – The Nitrogen fixator
  • Clostridium symbiosum-like – The rod-shaped
  • Firmicutes (Lachnospiraceae) – The fermenting expert
  • Actinobacteria – The green specialist
  • Bacteroidetes – The three legged
  • Clostridium thermosuccinogenes The hot one

Another cause that can be related to IBS-D are food allergies.  Many people report unpleasant outcomes after eating gluten or lactose products4. Products with lactose and gluten have been infamously known for decades as the nemesis of IBS5.

Gluten is a protein that can be found in popular grain products such as wheat or barley. Lactose on the other hand can be mostly found in dairy products such as milk or cheese. They are often blamed for many gastrointestinal issues and IBS symptoms. This is because people with IBS cannot break down this compounds in a proper way and end up being poorly absorbed by the intestine3,5.

However, lactose, gluten, or other food products and beverages are not necessarily the root of IBS or IBS-D, but can rather be the trigger of its symptoms making them harder to handle.

How to Stop IBS-D?

Symptoms can be treated but there is currently no cure for this condition. Research is moving forward, as is our understanding of IBS, ensuring potential new treatments are on the horizon!

How to Treat IBS-D?

Similar to IBS-C, the combination of several strategies may strengthen bowel movements and reduce the unpleasantries of IBS-D. For example, changing IBS diet plans, improving gut health, incorporating physiological therapies, and using both OTC and prescriptive IBS medications.

Although it has been documented that fiber can help reduce constipation, too much can be counter-effective for those with IBS-D, since doses may vary among individuals6.

Doctors and dieticians recommend a diet low in carbs or limited to those carbs that are easier to digest4.

Consuming certain food products can potentially help strengthen the gut and reduce IBS-D symptoms6. These dietary changes can be complemented with medical supplements such as antidiarrheals – medications that help to reduce the contractions of the bowel – and probiotics – good bacteria for the digestive system.

Gluten-free Diet (GFD) or dairy-free diets can be a potential pathway to deal with IBS-D symptoms. Several studies show improvements in IBS-D symptoms in patients avoiding dairy products. In two studies, 23 and 41 people with IBS-D showed significant improvement in their symptoms after adopting a GFD during a 6-week period. The results showed an improvement in stool frequency, less stool mucus, and lower depression levels3.

Common IBS-D Medications

  • Alosetron (Lotronex)
  • Eluxadoline (Viberzi)
  • Rifaximin (Xifaxan)
  • Antidiarrheal drugs
  • Bile-acid binders
  • Probiotics
  • Mast cell stabilizers
  • Antidepressants
  • K-opioid antagonists7


  1. Oka P, Parr H, Barberio B, Black CJ, Savarino E V., Ford AC. Global prevalence of irritable bowel syndrome according to Rome III or IV criteria: a systematic review and meta-analysis. Lancet Gastroenterol Hepatol. 2020;5(10):908-917. doi:10.1016/S2468-1253(20)30217-X
  2. Talley N. Overlapping upper and lower gastrointestinal symptoms in irritable bowel syndrome patients with constipation or diarrhea. Am J Gastroenterol. 2003;98(11):2454-2459. doi:10.1016/s0002-9270(03)00705-6
  3. Chong PP, Chin VK, Looi CY, Wong WF, Madhavan P, Yong VC. The microbiome and irritable bowel syndrome – A review on the pathophysiology, current research and future therapy. Front Microbiol. 2019;10(JUN). doi:10.3389/fmicb.2019.01136
  4. Lacy B, Patel N. Rome Criteria and a Diagnostic Approach to Irritable Bowel Syndrome. J Clin Med. 2017;6(11):99. doi:10.3390/jcm6110099
  5. Foley A, Burgell R, Barrett JS, Gibson PR. Management strategies for abdominal bloating and distension. Gastroenterol Hepatol. 2014;10(9):561-571. Accessed February 3, 2021. /pmc/articles/PMC4991532/?report=abstract
  6. Craddock D. Dietary advice. Bmj. 1983;286(6358):58-58. doi:10.1136/bmj.286.6358.58
  7. Khatri M. Medicines That Can Ease IBS-D Symptoms. WebMD Medical Reference. Published 2020. Accessed February 10, 2021. https://www.webmd.com/ibs/ibs-d-drugs#1

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