Written and medically reviewed by Fullscript’s Integrative Medical Advisory Team

Irritable bowel syndrome (IBS) is a common digestive health condition that can greatly impact quality of life. In a 2005 study of over 5,000 participants, IBS was found to affect 14% of people. In this case, 3.3% had a medical diagnosis and 10.8% met the diagnostic criteria of the disease but weren’t formally diagnosed. These findings indicate that IBS is significantly underdiagnosed and that many individuals with IBS may not be receiving necessary treatment from a practitioner. (14) Treatment for IBS may include dietary changes, supplementation, behavioral or lifestyle therapy, and medication.

Woman in sunlit room holding her stomach in pain

IBS symptoms include abdominal pain, bloating, and increased anxiety or depression.

What is IBS?

IBS is a group of functional disorders affecting the digestive tract that can cause daily or intermittent symptoms. Recurring intermittent symptoms can span weeks or even months. Since there aren’t any specific diagnostic tests available, the diagnosis of IBS is currently based on assessing a patient’s symptoms. The criteria developed to assess symptoms of the disease are called Rome criteria (I, II, III, and IV). (8)

IBS can be further broken down into subtypes based on the differences in bowel patterns:

  • IBS-D: diarrhea-predominant
  • IBS-C: constipation-predominant
  • IBS-M or IBS-A: a combination of both diarrhea and constipation (5)

Causes and risk factors

The pathophysiology of IBS is complex but is currently believed to result from dysfunction of the brain-gut axis. Central mechanisms include psychologic factors such as anxiety, depression, and somatization. The peripheral dysfunction occurs with changes in gut motility and secretion as well as visceral hypersensitivity (where inner organs are more sensitive to pain). Brain-gut dysfunction can also result from food hypersensitivity, increased mucosal permeability, and immune responses. (12)

Some triggers or risk factors include gastroenteritis, dietary triggers (specifically high-carbohydrate or high-fat foods), neurotic and psychologic disorders, and pain-related diseases. (24)

Signs and symptoms

Symptoms of IBS can vary depending on which subtype of the disorder you have. Common symptoms include:

  • Altered bowel habits: diarrhea, constipation, or a combination of the two
  • Recurrent abdominal pain or discomfort; characterized as visceral sensitivity
  • Increased levels of anxiety and depression
  • Fatigue and poor sleep
  • Comorbid pain disorders such as fibromyalgia and overactive bladder (in many patients) (9)(15)

Integrative protocol for digestive wellness

Essential oil dropper on table with peppermint leaves

Peppermint oil can be used internally to relieve abdominal pain with IBS.

Peppermint oil

Peppermint is well known as a culinary herb, a tea, and as an essential oil used in aromatherapy. The peppermint plant is a hybrid of spearmint and wild mint. The aerial parts (leaves) of peppermint contain about 2.4% essential oil, which is extracted by distillation. (7) Peppermint oil has been found to have antimicrobial, antiviral, and antioxidant effects. (2)(25)

Research findings:

  • Significant reduction of abdominal pain and global symptoms, relative to placebo (1)(3)
  • Benefits no longer present two weeks after supplement cessation (1)

US: Search for Peppermint Oil in the Fullscript catalog.
CAN: Search for Peppermint Oil in the Fullscript catalog.

Soluble dietary fiber

Dietary fiber can be generally categorized as soluble and insoluble. Soluble fiber dissolves in water and forms a viscous or jelly-like consistency. This consistency and ability to absorb water can help to slow the digestion of food. Research shows soluble fiber may have a positive effect on plasma cholesterol levels, and increase bile acid secretion. Bile acids are used to form bile salts, which then help the digestion and absorption of lipids (fat) in the GI tract. (13) A high amount of soluble fiber is found in many vegetables, fruit, grains, and legumes. Psyllium is the most commonly used soluble fiber supplement.

Research findings:

  • Safe and effective in improving global IBS symptoms, relative to placebo (16)
  • Form of soluble fiber used is important since short-chain soluble and highly fermentable dietary fiber can result in rapid gas production that can aggravate symptoms in patients with IBS (23)

US: Search for Fiber in the Fullscript catalog.
CAN: Search for Fiber in the Fullscript catalog.

Fermented food in jars on white backdrop

Probiotics are found in fermented foods such as sauerkraut, kimchi, and yogurt.


Your body contains an ecosystem of microflora that inhabits the skin and mucous membranes of the body. These include the respiratory tract, gastrointestinal (GI) tract, and vaginal tract in women. Maintaining a good balance in the GI tract between pathogenic and healthful bacteria is important to many aspects of health. Probiotics play a role in regulating digestion, absorbing nutrients, inhibiting pathogens, and producing neurotransmitters. Probiotics that come from food or supplements are called transient probiotics since they don’t inhabit the gut but have positive effects as they pass through the GI system. (11)

Research findings:

  • Effective in reducing symptoms and severity score in patients with IBS (6)
  • Specific strain recommendations remain to be concluded (10)(18)
  • Current recommendations suggest using an equal dosage of lactobacillus and bifidobacterium species (10)

US: Search for Probiotics in the Fullscript catalog.
CAN: Search for Probiotics in the Fullscript catalog.


L-glutamine is a non-essential amino acid abundant in the body. It plays a role in supporting immune function, including in cytokine production, neutrophil bacterial killing, and lymphocyte proliferation. (4) Considered conditionally essential in times of stress, such as injury or critical illness, l-glutamine aids in maintaining immune and intestinal function, as well as amino acid homeostasis. (21)(27) Specifically, studies demonstrate that l-glutamine supplementation can benefit gut barrier function, improve the body’s response to stress, and reduce the expression of proinflammatory cytokines. (27)

Research findings:

  • Glutamine has shown to improve intestinal permeability(17)(19)(20)(22)
  • Acute glutamine administration has been linked to a decrease of gastrointestinal symptoms and improvement in intestinal permeability in athletes competing in heat (20)

US: Search for L-Glutamine in the Fullscript catalog.
CAN: Search for L-Glutamine in the Fullscript catalog.

The bottom line

Symptoms of IBS can be debilitating in some, while mild in others. A protocol using natural supplements can be used therapeutically on its own or as an adjunct to existing treatment. If you are not an integrative healthcare provider, we recommend speaking with one to find out whether these supplements are right for your wellness plan.

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The Fullscript Integrative Medical Advisory team has developed or collected these protocols from practitioners and supplier partners to help health care practitioners make decisions when building treatment plans. By adding this protocol to your Fullscript template library, you understand and accept that the recommendations in the protocol are for initial guidance and may not be appropriate for every patient.

Fullscript Protocol for Digestive Wellness

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  1. Alam, M. S., Roy, P. K., Miah, A. R., Mollick, S. H., Khan, M. R., Mahmud, M. C., & Khatun, S. (2013). Efficacy of Peppermint oil in diarrhea predominant IBS – a double blind randomized placebo – controlled study. Mymensingh Medical Journal, 22(1), 27-30. Retrieved May 15, 2019, from https://www.ncbi.nlm.nih.gov/pubmed/23416804.
  2. Alankar, S. (2009). A REVIEW ON PEPPERMINT OIL. Asian Journal of Pharmaceutical and Clinical Research, 2(2), 27-33. Retrieved May 15, 2019, from https://innovareacademics.in/journal/ajpcr/Vol2Issue2/187.pdf.
  3. Cappello, G., Spezzaferro, M., Grossi, L., Manzoli, L., & Marzio, L. (2007). Peppermint oil (Mintoil®) in the treatment of irritable bowel syndrome: A prospective double blind placebo-controlled randomized trial. Digestive and Liver Disease, 39(6), 530-536.
  4. Cruzat, V., Macedo Rogero, M., Noel Keane, K., Curi, R., & Newsholme, P. (2018). Glutamine: metabolism and immune function, supplementation and clinical translation. Nutrients, 23, 10(11).
  5. Definition & Facts for Irritable Bowel Syndrome. (2017, November 01). Retrieved May 15, 2019, from https://www.niddk.nih.gov/health-information/digestive-diseases/irritable-bowel-syndrome/definition-facts
  6. Didari, T., Mozaffari, S., Nikfar, S., & Abdollahi, M. (2015). Effectiveness of probiotics in irritable bowel syndrome: Updated systematic review with meta-analysis. World Journal of Gastroenterology, 21(10), 3072-3084.
  7. Duband, F., Carnat, A. P., Carnat, A., Petitjean-Freytet, C., Clair, G., & Lamaison, J. L. (1992). [Aromatic and polyphenolic composition of infused peppermint, Mentha x piperita L]. Annales Pharmaceutiques Françaises, 50(3), 146-155. Retrieved May 15, 2019, from https://www.ncbi.nlm.nih.gov/pubmed/1290384?dopt=Abstract.
  8. El-Salhy, M. (2012). Irritable bowel syndrome: Diagnosis and pathogenesis. World Journal of Gastroenterology, 18(37), 5151-5163.
  9. Enck, P., Aziz, Q., Barbara, G., Farmer, A. D., Fukudo, S., Mayer, E. A., . . . Spiller, R. C. (2016). Irritable bowel syndrome. Nature Reviews Disease Primers, 2(16014).
  10. Ford, A. C., Quigley, E. M., Lacy, B. E., Lembo, A. J., Saito, Y. A., Schiller, L. R., . . . Moayyedi, P. (2014). Efficacy of Prebiotics, Probiotics and Synbiotics in Irritable Bowel Syndrome and Chronic Idiopathic Constipation: Systematic Review and Meta-analysis. The American Journal of Gastroenterology, 109(10), 1547-1561.
  11. Galveston, C. P. (n.d.). Medical Microbiology (4th ed.) (S. Baron, Ed.). S.l.: University of Texas Medical Branch at Galveston. Retrieved May 15, 2019, from https://www.ncbi.nlm.nih.gov/books/NBK7617/.
  12. Giovanni, B., Cremon, C., Carini, G., Bellacosa, L., Zecchi, L., De Giorgio, R., . . . Stanghellini, V. (2011). The Immune System in Irritable Bowel Syndrome. Journal of Neurogastroenterology and Motility, 17(4), 349-359.
  13. Grundy, M. M., Edwards, C. H., Mackie, A. R., Gidley, M. J., Butterworth, P. J., & Ellis, P. R. (2016). Re-evaluation of the mechanisms of dietary fibre and implications for macronutrient bioaccessibility, digestion and postprandial metabolism. British Journal of Nutrition, 116(5), 816-833.
  14. Hungin, A. P., Chang, L., Locke, G. R., Dennis, E. H., & Barghout, V. (2005). Irritable bowel syndrome in the United States: Prevalence, symptom patterns and impact. Alimentary Pharmacology and Therapeutics, 21(11), 1365-1375.
  15. Labus, J., Gupta, A., Gill, H. K., Posserud, I., Mayer, M., Raeen, H., . . . Mayer, E. A. (2014). Randomized Clinical Trial: Moderators and Mediators of a Psycho-education Group Intervention on IBS Symptoms. Alimentary Pharmacology & Therapeutics, 37(3).
  16. Moayyedi, P., Quigley, E. M., Lacy, B. E., Lembo, A. J., Saito, Y. A., Schiller, L. R., . . . Ford, A. C. (2014). The effect of fiber supplementation on irritable bowel syndrome: A systematic review and meta-analysis. American Journal of Gastroenterology, 109(9), 1367-1374.
  17. Mottaghi, A., Yeganeh, M. Z., Golzarand, M., Jambarsang, S., & Mirmiran, P. (2016). Efficacy of glutamine-enriched enteral feeding formulae in critically ill patients: a systematic review and meta-analysis of randomized controlled trials. Asia Pacific Journal of Clinical Nutrition, 25(3), 504-12.
  18. Newlove‐Delgado, T. V., Martin, A. E., Abbott, R. A., Bethel, A., Thompson-Coon, J., Whear, R., & Logan, S. (2017). Dietary interventions for recurrent abdominal pain in childhood. Cochrane Database Systematic Review, 23(3).
  19. Peng, X., Yan, H., You, Z., Wang, P., & Wang, S. (2004). Effects of enteral supplementation with glutamine granules on intestinal mucosal barrier function in severe burned patients. Burns, 30(2), 135-9.
  20. Pugh, J. N., Sage, S., Hutson, M., Doran, D. A., Fleming, S. C., Highton, J., … Close, G. L. (2017). Glutamine supplementation reduces markers of intestinal permeability during running in the heat in a dose-dependent manner. European Journal of Applied Physiology, 117(12), 2569-2577.
  21. Sacks, G. S. (1999). Glutamine supplementation in catabolic patients. Annals of Pharmacotherapy, 33(3), 348-54.
  22. Sevastiadou, S., Malamitsi-Puchner, A., Costalos, C., Skouroliakou, M., Briana, D.D., Antsaklis, A., & Roma-Giannikou, E. (2011). The impact of oral glutamine supplementation on the intestinal permeability and incidence of necrotizing enterocolitis/septicemia in premature neonates. The Journal of Maternal-Fetal & Neonatal Medicine, 24(10), 1294-300.
  23. Shah, S. L., & Lacy, B. E. (2016). Dietary Interventions and Irritable Bowel Syndrome: A Review of the Evidence. Current Gastroenterology Reports, 18(8).
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  27. Wischmeyer, P. E., Dhaliwal, R., McCall, M., Ziegler, T. R., & Heyland, D. K. (2014). Parenteral glutamine supplementation in critical illness: a systematic review. Critical Care, 18(2), R76.