IBS Medication: A Sales-Free Look At What Works

Irritable bowel syndrome (IBS) is an increasingly common digestive disorder.

Almost one in five people will experience it at some point in their life, with women more prone than men.

Unfortunately the cause of IBS is unknown, making it difficult to know what the best treatment is.

This article looks into the various forms of IBS medication currently recommended.

IBS Types and Treatments

IBS-Types-and-Treatments 2

Irritable bowel syndrome (IBS) is a gastrointestinal disorder characterised by recurrent digestive stress.

It can be categorised into three different types based on its symptoms:

  • diarrhea dominant (IBS-D)
  • constipation dominant (IBS-C)
  • or alternating/mixing between diarrhea and constipation (IBS-M).

There are many different medications available to help treat those IBS symptoms. Some can help with diarrhea or constipation, while others treat abdominal pain, bloating and flatulence.

Summary: IBS is categorized by its symptoms, specifically diarrhea, constipation or both. There are many medications available, depending on the dominant symptoms.

Diarrhea Medication

There are many proven ways to manage chronic diarrhea.

There are also many medications available for treating IBS-D specifically.

Here are the most common types:

Rifaximin (Xiafaxan)

  • diarrhea or stomach pain, character design - vectorAn antibiotic used to treat IBS-D and relieve abdominal pain and flatulence.
  • Appears to be well tolerated in patients, with minimal side effects.
  • Recent studies have found that 40% of patients who took a 2-week course of Rifaximin saw an improvement in their IBS symptoms during the first 4 weeks after treatment (1, 2).
  • Should be taken before a low FODMAP diet.


  • Helps relax the colon (large intestine) and prevent diarrhea.
  • Is only recommended for women with severe IBS-D, who have not responded to other treatments (1).
  • There’s also a risk of harmful side effects, including ischemic colitis (inflammation of the large intestine) and complications of constipation (1, 3).
  • In a study that tested different dosages of Alosetron, those who took the lowest dose (0.5mg daily) reported the greatest reduction in symptoms (51%) and fewer reports of side effects (4) .

Eluxadoline (Viberzi)

  • Viberzi helps slow the movement of poop through the digestive system.
  • Some people should not take this medication, including those with a history of pancreatitis, liver complications and/or a high alcohol intake (13).
  • Constipation can be a side effect. There has also been a number of cases in which people have developed pancreatitis (inflammation of the pancreas) from taking Eluxadoline (4).

Loperamide (Imodium/Gastro-Stop) and Atropine (Lomotil)

  • Anti-diarrheal medications are effective at stopping diarrhea and farting but provide no benefit in relieving abdominal pain or bloating. In fact, they can sometimes cause stomach cramps and pain (3).
  • There have also been reports of overdosing (with very large doses), which can cause heart complications (5).

Summary: Several medications can treat IBS-D, most requiring a prescription from your doctor. Rifaximin, Alosetron, and Eluxadoline have all shown to be effective, though many come with side effects.

Constipation Medication

Constipation Medication

There are many proven way to treat chronic constipation.

But there are also many medications available to treat IBS-C.

Here are the most common types:


  • Helps soften stools, making it easier to pass without straining.
  • Can also help with stomach pain and bloating.
  • High doses can cause feelings of nausea and should always be taken with food and water (1).
  • In a 12-week study, 18% of participants taking Lubiprostone reported improvements in both constipation and abdominal pain (6).


  • Helps move undigested food (waste) through the digestive system, making it easier to pass.
  • Relief from constipation happens within about a week; however, improvements in abdominal pain and bloating can take up to 8-12 weeks (1).
  • High doses can sometimes result in diarrhea (1).

Stimulant Laxatives (Senna, Aloe, Bisacodyl, Castor Oil)

  • Laxatives are available in pharmacies without a prescription.
  • They help stimulate the bowel in various ways to relieve constipation.
  • Stimulant laxatives don’t provide relief from abdominal pain or discomfort.
  • This type of medication should not be taken long term as they can make the bowel become lazy and dependant on laxatives.

Osmotic Laxatives (Macragol, Polyethylene Glycol, Milk of Magnesia)

  • Osmotic laxatives help draw water into the large intestine (bowel), making it easier to pass stool.
  • Like stimulant laxatives, they only provide relief from constipation and don’t treat abdominal pain/discomfort or bloating. In fact, they can often cause these symptoms.

Summary: Both prescription and non-prescription medications are available to treat constipation. Evidence suggests Lubiprostone and Linaclotide may provide the greatest benefit in relieving IBS-C.

Abdominal Pain and Bloating Medication

Abdominal Pain and Bloating Medication

There are numerous natural ways to manage bloating.

But certain medications can be used to target the specific IBS symptoms of abdominal pain and bloating.

These include:

Antispasmodics (Hyoscyamine, Dicyclomin)

  • These help relieve stomach cramps caused by diarrhea or constipation by relaxing the muscles around the abdomen.
  • High doses can lead to constipation, fatigue, dry mouth, dizziness and blurred vision (6).

Peppermint Oil

  • This is an essential oil extracted from the peppermint plant.
  • When taken in capsule form, peppermint oil has been shown to be very effective in relieving abdominal pain and bloating.
  • A new formulation of peppermint oil has recently been introduced in the United States and is likely safe. A study found that 40% of patients taking this formulation had reduced abdominal pain/discomfort and bloating, a significantly greater percentage than patients who took a placebo (7).

Summary: Antispasmodics and peppermint appear to help with abdominal pain and bloating.

All IBS Symptoms Medication

All IBS Symptoms Medication

Some medications can be used to treat multiple IBS symptoms rather than just targeting one symptom.

These include:

Selective Serotonin Reuptake Inhibitors (SSRIs)

  • These are usually prescribed as antidepressants, but they’ve also shown to help move contents through the digestive system, preventing constipation.
  • Studies have shown that SSRIs need to be taken between 4-8 weeks before symptoms are improved (1).
  • Several randomised controlled trials (RCTs) found that SSRIs are no better at relieving the symptoms of IBS than a placebo (1, 8).
  • Side effects can include poor sleep, headaches, anxiety and nausea.

Tricyclic Antidepressants (TCAs)

  • This is another group of antidepressants that can help move contents through the digestive system.
  • An advantage of TCAs is that they can also help with abdominal pain and bloating, and improve mood. (1)
  • Several studies have shown that TCAs are better at improving IBS symptoms when compared to a placebo (89).
  • Side effects can include dry mouth and drowsiness.

Summary: Two types of antidepressants, selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs), have been shown to reduce multiple symptoms of IBS, the latter showing more effective results. However, various side effects can make it difficult to use this type of medication long term.

Non-Medicated Approaches


There are some non-medicated approaches for treating IBS as well.

Peppermint Oil

  • As mentioned above, peppermint oil has been shown to be very effective in relieving abdominal pain and bloating.
  • Peppermint oil works as a muscle relaxant and may work as anti-inflammatory.
  • A review of a small number of clinical trials found that peppermint oil was significantly better at improving IBS symptoms than the placebo (10).
  • Heart burn, dry mouth and burping can be common side effects of taking peppermint oil.


  • IBgard is a new formulation of peppermint oil recently introduced in the United States.
  • Limited studies have been conducted on the effectiveness of IBgard.
  • One study has found that patients taking this formulation noticed a 40% reduction in abdominal pain/discomfort and bloating, which was significantly greater than patients who took a placebo (11).
  • IBgard does cause side effects like regular peppermint oil.


  • Iberogast is a herbal formulation containing nine herbal plant extracts.
  • It may relieve IBS symptoms by helping to move contents through the digestive system and reduce abdominal pain (12, 13)
  • In a study of 282 patients, Iberogast was found to be significantly better at reducing abdominal pain and IBS symptoms than the placebo after a 4 week trial (14).


  • Fiber is a type of carbohydrate that helps to keep our bowel movements regular and constipation may occur from a low fiber diet.
  • Some studies suggest a fibre supplement can improve the symptoms of IBS-C.
  • Soluble fiber, such as psyllium husk, has shown to be more beneficial than insoluble fibre, such as wheat bran in those with IBS-C (15).
  • Insoluble fiber can often make IBS symptoms worse, leading to bloating, flatulence, and abdominal discomfort (16).
  • In a study of 275 adults with IBS, soluble fiber was significantly more effective than the placebo in improving symptoms (15).
  • Fiber is best introduced slowly into the diet. Increasing the amount of water you drink is also important to prevent constipation.
  • A high fiber diet also has other health benefits including reducing the risk of heart disease and type 2 diabetes and can help maintain a healthy body weight (17)

Changes in diet (such as a low FODMAP approach), and psychological treatments (hypnotherapy, cognitive behavioural therapy and mindfulness meditation) should also be considered when managing IBS.

There is also some evidence that a probiotic supplement can help with the symptoms. There are many different types (species, strains, preparations) of probiotics, which I have reviewed here.

Summary: There are also ways to treat IBS without relying on medication. These include herbal formulations, probiotics, a low-FODMAP diet and psychological therapy.

IBS Medication Can Be A Useful Part of Treatment

IBS is a complicated condition.

There are not only many different causes, but different treatment options available depending on your symptoms and poop health.

You should not be afraid to try some IBS medications (under the recommendation of your doctor), but at the same time do not rely on them as the only form of treatment.

Research shows that both medical and non-medical approaches work hand-in-hand to achieve the best treatment outcomes for patients.


About Joe Leech, Dietitian (MSc Nutrition & Dietetics)

Joe Leech is a university-qualified dietitian from Australia.

He graduated with a Bachelor's degree in exercise science, followed by a Master's degree in Nutrition and Dietetics in 2011.

Learn more about him on the About page