What is IBS?

Definition

Irritable Bowel Syndrome (IBS) stands as a common condition that alters the way your gut (especially your large intestine) works. IBS can cause tummy pain, bloating, and changes in bowel habits — such as going to the bathroom more or less often than normal, or producing different styles of stool(poop).

IBS is a long-term (chronic)condition, but with adequate lifestyle changes and proper treatment strategies, many people manage it properly! (Colomier, E. et al. 2021)

IBS can have different presentations, it does not present in the same way to each individual. Doctors commonly group it into the specific kind of bowel movement each patient has, these are the following:

TYPES OF IBS

IBS is classified into different subtypes based on the predominant bowel habits. Understanding your specific subtype can help guide more effective treatment.

IBS-C (Constipation-predominant): You frequently experience hard or lumpy stools and may struggle to go to the bathroom.
IBS-D (Diarrhea-predominant): Most of your stools are loose or watery, and you may get the urge to go urgently or more frequently.
IBS-M (Mixed): You experience both constipation and diarrhea at different times.
IBS-U (Unsubtyped): Your symptoms don’t clearly belong in one of the other three categories.

(Di Rosa, C. et al. 2024; Hung, T. H. et al. 2023)

Causes & Risk Factors

Post-infectious IBS

Psychological Factors

Post-infectious IBS

Occasionally, people get IBS after a bad stomach infection (such as food poisoning or a stomach bug). The gut can remain sensitive or irritated even after the infection resolves (Jianan, Y- et al. 2025)

Gut-Brain Axis

Psychological Factors

Post-infectious IBS

Your gut and your brain are tightly linked, scientists in recent times have called this connection the gut-brain axis. Stress, anxiety, or even strong emotions can influence the workings of your gut. That’s why some folks get some tummy trouble when stressed. Changes in this gut-brain connection can trigger or worsen IBS (García Mansilla, M. J. et al. 2025)

Psychological Factors

Stress, anxiety and depression don’t trigger IBS, but they can aggravate the symptoms. Those who have irritable bowel syndrome may also experience increasingly more trouble at times when they are dealing with emotional or mental stressors (Wang, J. et al. 2024)

Symptoms

What Symptoms Do People with IBS Usually Experience?

People which live with Irritable Bowel Syndrome (IBS) can present with varying symptoms, but these are the ones that present most commonly

Abdominal pain or cramping: Typically relieved by using the bathroom.
Bloat or swelling in the belly
Changesin bowel habits, such as:
- Diarrhea (loose, frequent stools)
- Constipation (stools that are hard and difficult to pass)
- Concurrent diarrhoea and constipation
A sense that you haven’t completed a bowel movement
Gas or excessive flatulence

(Choi, Y. et al. 2025)

Bristol Stool Scale

The Bristol Stool Scale is a simple tool that helps you (and your doctor) understand what your poop says about your gut health. It was created by doctors in the UK to help people describe their stool consistency without feeling embarrassed or unsure.

There are seven types, ranging from hard lumps to completely liquid. Each type gives clues about how fast or slow things are moving through your intestines.

Why It Matters for IBS

If you're living with Irritable Bowel Syndrome (IBS), your bowel habits are one of the key signs your healthcare provider will look at. The Bristol Stool Scale helps identify your IBS subtype, which can make a big difference in how your symptoms are treated

(Stanford Medicine. 2025)

"Red flag" symptoms not to ignore

Most people with IBS don’t have serious underlying conditions—but it’s still important to be aware of certain signs that should never be ignored. If you notice any of the following, please schedule a medical check-up to make sure everything is okay:

Blood in your stool
Unexplained weight loss
Ongoing fever
Frequently waking up during the night to have a bowel movement
A new lump or swelling in your abdomen
A family history of colon cancer, inflammatory bowel disease (IBD), or celiac disease

These symptoms may not be caused by IBS, so getting checked can help rule out other conditions and give you peace of mind.

(Choi, Y. et al., 2025)

REFERENCES

Choi, Y., Youn, Y. H., Kang, S. J., Shin, J. E., Cho, Y. S., Jung, Y. S., Shin, S. Y., Huh, C. W., Lee, Y. J., Koo, H. S., Nam, K., Lee, H. S., Kim, D. H., Park, Y. H., Kim, M. C., Song, H. Y., Yoon, S. H., Lee, S. Y., Choi, M., Park, M. I., … Korean Society of Neurogastroenterology and Motility (2025). 2025 Seoul Consensus on Clinical Practice Guidelines for Irritable Bowel Syndrome. Journal of neurogastroenterology and motility, 31(2), 133–169. https://doi.org/10.5056/jnm25007
Colomier, E., Algera, J., & Melchior, C. (2021). Pharmacological Therapies and Their Clinical Targets in Irritable Bowel Syndrome With Diarrhea. Frontiers in pharmacology, 11, 629026. https://doi.org/10.3389/fphar.2020.629026
Di Rosa, C., Van den Houte, K., Altomare, A., Guarino, M. P. L., Besard, L., Arts, J., Caenepeel, P., Piessevaux, H., Vandenberghe, A., Matthys, C., Biesiekierski, J. R., Capiau, L., Ceulemans, S., Gernay, O., Jones, L., Maes, S., Peetermans, C., Raat, W., Stubbe, J., Van Boxstael, R., … Carbone, F. (2024). DOMINO trial post hoc analysis: evaluation of the diet effects on symptoms in IBS subtypes.
Jianan, Y., Kunming, C., Chao, L. I., Xiang, Z., Zeyu, D., Bing, L. I., & Yongqiu, Z. (2025). Atractylenolide I ameliorates post-infectious irritable bowel syndrome by inhibiting the polymerase I and transcript release factor and c-Jun N-terminal kinase/inducible nitric oxide synthase pathway. Journal of traditional Chinese medicine = Chung i tsa chih ying wen pan, 45(1), 57–65. https://doi.org/10.19852/j.cnki.jtcm.2025.01.006
Therapeutic advances in gastroenterology, 17, 17562848241255296. https://doi.org/10.1177/17562848241255296
Hung, T. H., Wang, C. Y., & Lee, H. F. (2023). Update in diagnosis and management of irritable bowel syndrome. Tzu chi medical journal, 35(4), 306–311. https://doi.org/10.4103/tcmj.tcmj_104_23
Mansilla, M. J., Rodríguez Sojo, M. J., Lista, A. R., Ayala Mosqueda, C. V., Ruiz Malagón, A. J., Ho Plagaro, A., Gálvez, J., Rodríguez Nogales, A., & Rodríguez Sánchez, M. J. (2025). Microbial-Derived Antioxidants in Intestinal Inflammation: A Systematic Review of Their Therapeutic Potential. Antioxidants (Basel, Switzerland), 14(3), 321. https://doi.org/10.3390/antiox14030321
Saha L. (2014). Irritable bowel syndrome: pathogenesis, diagnosis, treatment, and evidence-based medicine. World journal of gastroenterology, 20(22), 6759–6773. https://doi.org/10.3748/wjg.v20.i22.6759
Stanford Medicine. (2025). Bristol Stool Form scale. Pediatric General Surgery. Recuperado 15 de abril de 2025, de https://pediatricsurgery.stanford.edu/Conditions/BowelManagement/bristol-stool-form-scale.html
Wang, J., Meng, N., Chen, K., Huang, X., Feng, L., Yang, C., Li, Z., & Sun, X. (2024). The Relationship Between Depressive Symptoms and Functional Gastrointestinal Disorders (FGIDs): The Chain Mediating Effect of Sleep Disorders and Somatic Symptom. Depression and anxiety, 2024, 5586123. https://doi.org/10.1155/2024/5586123

What is IBS?

Definition

TYPES OF IBS

Causes & Risk Factors

Post-infectious IBS

Psychological Factors

Post-infectious IBS

Gut-Brain Axis

Psychological Factors

Post-infectious IBS

Psychological Factors

Psychological Factors

Psychological Factors

Symptoms

What Symptoms Do People with IBS Usually Experience?

One day constipation, next day diarrhea? IBS can’t make up its mind – but you can learn to outsmart it.

Bristol Stool Scale

Why It Matters for IBS

"Red flag" symptoms not to ignore

Type 3 or 4 = happy gut. Celebrate the small wins!

REFERENCES