Irritable bowel syndrome affects between 6–18% of people worldwide.
This condition involves changes in frequency or form of bowel movements and lower abdominal pain.
Diet, stress, poor sleep, and changes in gut bacteria may all trigger symptoms.
However, triggers are different for each person, making it difficult to name specific foods or stressors that everyone with the disorder should avoid.
This article will discuss the most common symptoms of irritable bowel syndrome and what to do if you suspect you have it.
1. Pain and cramping
Abdominal pain is the most common symptom and a key factor in diagnosis.
Normally, your gut and brain work together to control digestion. This happens via hormones, nerves, and signals released by the good bacteria that live in your gut.
In irritable bowel syndrome, these cooperative signals become distorted, leading to uncoordinated and painful tension in the muscles of the digestive tract.
This pain usually occurs in the lower abdomen or the entire abdomen but is less likely to be in the upper abdomen alone. Pain typically decreases following a bowel movement.
Diet modifications, such as a diet low in FODMAPs, may improve pain and other symptoms.
Other treatments include bowel relaxants like peppermint oil, cognitive behavior therapy, and hypnotherapy.
For pain that doesn’t respond to these changes, a gastroenterologist can help you find a medication specifically proven to ease irritable bowel syndrome pain.
Summary: The most common symptom of irritable bowel syndrome is lower abdominal pain that is less severe after a bowel movement. Dietary modifications, stress-reducing therapies, and certain medications can help reduce pain.
2. Diarrhea
Diarrhea-predominant irritable bowel syndrome is one of the three main types of the disorder. It affects roughly one-third of patients with irritable bowel syndrome.
A study of 200 adults found that those with diarrhea-predominant irritable bowel syndrome had, on average, 12 bowel movements weekly — more than twice the amount of adults without irritable bowel syndrome.
Accelerated bowel transit in irritable bowel syndrome can also result in a sudden, immediate urge to have a bowel movement. Some patients describe this as a significant source of stress, even avoiding some social situations for fear of a sudden onset of diarrhea.
Additionally, stool in the diarrhea-predominant type tends to be loose and watery and may contain mucus.
Summary: Frequent, loose stools are common in irritable bowel syndrome and are a symptom of the diarrhea-predominant type. Stools may also contain mucus.
3. Constipation
Although it seems counterintuitive, irritable bowel syndrome can cause constipation as well as diarrhea.
Constipation-predominant irritable bowel syndrome is the most common type, affecting nearly 50% of people with irritable bowel syndrome.
Altered communication between the brain and bowel may speed up or slow down the normal transit time of stool. When transit time slows, the bowel absorbs more water from stool, and it becomes more difficult to pass.
Constipation is defined as having fewer than three bowel movements per week.
“Functional” constipation describes chronic constipation not explained by another disease. It is not related to irritable bowel syndrome and is very common. Functional constipation differs from irritable bowel syndrome in that it is generally not painful.
In contrast, constipation in irritable bowel syndrome includes abdominal pain that eases with bowel movements.
Constipation in irritable bowel syndrome also often causes a sensation of an incomplete bowel movement. This leads to unnecessary straining.
Along with the usual treatments for irritable bowel syndrome, exercise, drinking more water, eating soluble fiber, taking probiotics and the limited use of laxatives may help.
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Summary: Constipation is very common. However, abdominal pain that improves after a bowel movement and a sensation of incomplete bowel movements after passing stool are signs of irritable bowel syndrome.
4. Alternating constipation and diarrhea
Mixed or alternating constipation and diarrhea affect about 20% of patients with irritable bowel syndrome.
Diarrhea and constipation in irritable bowel syndrome involve chronic, recurring abdominal pain. Pain is the most important clue that changes in bowel movements are not related to diet or common, mild infections.
This type of irritable bowel syndrome tends to be more severe than the others with more frequent and intense symptoms.
The symptoms of mixed irritable bowel syndrome also vary more from one person to another. Therefore, this condition requires an individualized treatment approach rather than “one-size-fits-all” recommendations.
Summary: About 20% of patients with irritable bowel syndrome experience alternating periods of diarrhea and constipation. Throughout each phase, they continue to experience pain relieved by bowel movements.
5. Changes in bowel movements
Slow-moving stool in the intestine often becomes dehydrated as the intestine absorbs water. In turn, this creates hard stool, which can exacerbate symptoms of constipation.
Prompt movement of stool through the intestine leaves little time for absorption of water and results in the loose stools characteristic of diarrhea.
Irritable bowel syndrome can also cause mucus to accumulate in stool, which is not usually associated with other causes of constipation.
Blood in the stool may be a sign of another, potentially serious medical condition and deserves a visit to your doctor. Blood in the stool may appear red but often appears very dark or black with a tarry consistency.
Summary: irritable bowel syndrome changes the time stool remains in your intestines. This changes the amount of water in the stool, giving it a range from loose and watery to hard and dry.
6. Gas and bloating
Altered digestion in irritable bowel syndrome leads to more gas production in the gut. This can cause bloating, which is uncomfortable.
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Many with irritable bowel syndrome identify bloating as one of the most persistent and nagging symptoms of the disorder.
In a study of 337 irritable bowel syndrome patients, 83% reported bloating and cramping. Both symptoms were more common in women and constipation-predominant irritable bowel syndrome or mixed types of irritable bowel syndrome.
Avoiding lactose and other FODMAPs can help reduce bloating.
Summary: Gas and bloating are some of the most common and frustrating symptoms of irritable bowel syndrome. Following a low-FODMAPs diet can help reduce bloating.
7. Food intolerance
Up to 70% of individuals with irritable bowel syndrome report that particular foods trigger symptoms.
Two-thirds of people with irritable bowel syndrome actively avoid certain foods. Sometimes these individuals exclude multiple foods from their diet.
Why these foods trigger symptoms is unclear. These food intolerances are not allergies, and trigger foods don’t cause measurable differences in digestion.
While trigger foods are different for everyone, some common ones include gas-producing foods, such as FODMAPs, as well as lactose and gluten.
Summary: Many people with irritable bowel syndrome report specific trigger foods. Some common triggers include FODMAPs and stimulants, such as caffeine.
8. Fatigue and difficulty sleeping
Over half of people with irritable bowel syndrome report fatigue.
In one study, 160 adults diagnosed with irritable bowel syndrome described low stamina that limited physical exertion in work, leisure, and social interactions.
Another study of 85 adults found that the intensity of their symptoms predicted the severity of fatigue.
Irritable bowel syndrome is also related to insomnia, which includes difficulty falling asleep, waking frequently, and feeling unrested in the morning.
In a study of 112 adults with irritable bowel syndrome, 13% reported poor sleep quality.
Another study of 50 men and women found that those with irritable bowel syndrome slept about an hour longer yet felt less refreshed in the morning than those without irritable bowel syndrome.
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Interestingly, poor sleep predicts more severe gastrointestinal symptoms the following day.
Summary: Those with irritable bowel syndrome are more fatigued and report less refreshing sleep compared to those without it. Fatigue and poor sleep quality are also related to more severe gastrointestinal symptoms.
9. Anxiety and depression
Irritable bowel syndrome is linked to anxiety and depression, as well.
It’s unclear whether irritable bowel syndrome symptoms are an expression of mental stress or whether the stress of living with irritable bowel syndrome makes people more prone to psychological difficulties.
Whichever comes first, anxiety and digestive irritable bowel syndrome symptoms reinforce one another in a vicious cycle.
In a large study of 94,000 men and women, people with irritable bowel syndrome were over 50% more likely to have an anxiety disorder and over 70% more likely to have a mood disorder, such as depression.
Another study compared levels of the stress hormone cortisol in patients with and without irritable bowel syndrome. Given a public speaking task, those with irritable bowel syndrome experienced greater changes in cortisol, suggesting greater stress levels.
Additionally, another study found that anxiety reduction therapy reduced stress and irritable bowel syndrome symptoms.
Summary: irritable bowel syndrome can produce a vicious cycle of digestive symptoms that increase anxiety and anxiety that increases digestive symptoms. Tackling anxiety can help reduce other symptoms.
What to do if you think you have irritable bowel syndrome
If you have symptoms of irritable bowel syndrome that interfere with your quality of life, visit a primary care doctor near you, who can help diagnose irritable bowel syndrome and rule out other diseases that mimic it. If you don’t already have a physician, you can use the Healthline FindCare tool to find a provider near you.
Irritable bowel syndrome is diagnosed by recurrent abdominal pain for at least 6 months, combined with weekly pain for 3 months as well as some combination of pain relieved by bowel movements and changes in frequency or form of bowel movements.
Your doctor may refer you to a gastroenterologist, a specialist in digestive diseases, who can help you identify triggers and discuss ways to control your symptoms.
Lifestyle changes, such as a low-FODMAPs diet, stress relief, exercise, drinking plenty of water, and over-the-counter laxatives can also help. Interestingly, a low-FODMAPs diet is one of the most promising lifestyle changes for alleviating symptoms.
Identifying other trigger foods can be difficult, as these are different for each person. Keeping a diary of meals and ingredients can help identify triggers.
Probiotic supplements may also reduce symptoms.
Additionally, avoiding digestive stimulants, such as caffeine, alcohol, and sugary beverages, can reduce symptoms in some people.
If your symptoms don’t respond to lifestyle changes or over-the-counter treatments, there are several medications proven to help in difficult cases.
If you think you have irritable bowel syndrome, consider keeping a journal of foods and symptoms. Then, take this information to your doctor to help diagnose and control the condition.
