The main symptoms of IBS are belly pain with constipation or diarrhea. IBS is quite common, but most people's symptoms are so mild that they never see a doctor for treatment. Some people may have troublesome symptoms. Symptoms of IBS include:

• Changes in bowel movement patterns.
• Bloating and excess gas.
• Pain the lower belly.
• Mucus in stools.

You are more likely to have IBS if you have these symptoms and they have lasted at least 6 months, you have had belly pain at least 3 days each month for at least 3 months, and at least two of the following are true:

• The pain is relieved by having a bowel movement.
• The pain is linked to a change in how often you have a bowel movement.
• The pain is linked to a change in the look or texture of your stool.

Because there are no structural problems in the intestines of people who have IBS, some people may think this means that the symptoms "are all in their head." This isn't true. The pain, discomfort, and bloating are real.

Bowel movement patterns

When you have IBS, your pattern of bowel movements may be different over time. Two or more of the following may happen:

• Bowel movements may occur either more often (diarrhea) or less often (constipation) than usual. For example, you may have more than 3 bowel movements a day or less than 3 a week.
• Bowel movements may differ in size or consistency. They may be hard and small, pencil-thin, or loose and watery.
• The way stools pass changes. You may strain, feel an urgent need to have a bowel movement, or feel that you haven't completely passed a stool.
• You may have bloating or a feeling of gas in the intestines.

Many people with IBS go back and forth between having constipation and having diarrhea.

Other intestinal symptoms

Some people may have pain in the lower belly with constipation that is sometimes followed by diarrhea. Other people have pain and mild constipation but no diarrhea.

Some people have intestinal gas, and they pass mucus in their stools.