Irritable bowel syndrome (IBS) can be divided into different types, depending on which digestive symptoms show up the most. Knowing what type you have is important because some IBS treatment options only work on certain types.

If you and your healthcare provider are trying to figure out what type of IBS you’re living with, there are a few points you should know. Understanding what to look for and what distinguishes each type can help you get the correct diagnosis.

Types of IBS

How many types of IBS are there? Some doctors say that there are three different kinds:

• IBS with constipation (IBS-C)
• IBS with diarrhea (IBS-D)
• IBS with mixed bowel habits (IBS-M)

Others include a fourth type, called IBS-U. We’ll cover all four types in this article. But don’t be surprised if your gastroenterologist only talks about three: constipation, diarrhea, and mixed. IBS-U is used less often in practice.

Types of IBS Described

IBS is diagnosed using the Rome criteria (a standard set of symptom-based rules). There’s no single lab test that confirms IBS. However, some common symptoms of IBS may show up in all of the different types. Gastroenterology teams often see people experiencing:

• Stomach cramping or abdominal pain, often connected to a need to poop
• Unusual pooping habits, like diarrhea or constipation, or going back and forth between the two
• Bloating and gas in the stomach and intestines
• A feeling that you can’t empty your bowels
• Mucus in your poop that may look white

To tell IBS types apart, doctors look at stool form on days with symptoms, using the Bristol Stool Form Scale. Researchers don’t know the cause of IBS or why you have one type and not another.

1. IBS-C

In this type of IBS, you’re more likely to experience constipation. When you’re thinking about what type of IBS you might have, make sure you only consider the days when you have abnormal bowel movements. If this doesn’t happen to you every day, only focus on the days when it does.

On those days, for IBS-C, more than a quarter of the time that you poop, your poop will look lumpy or hard. In addition, on that same day, less than a quarter of your stools will be soft and watery. If this sounds like you, it could mean you have IBS-C.

People with IBS-C report, on average, that they have gas, bloating, and pain in their gut about 200 days each year.

They may also struggle with:

• Straining when they’re on the toilet
• Feeling nauseated
• Not pooping enough
• Not being able to empty their bowels completely when they poop

One large study from BMC Gastroenterology showed that people with IBS-C may experience more depression and anxiety than those with other types of IBS. More research is needed to confirm whether this is true, and if it is, why it happens.

There are several different medication options for IBS-C. Your doctor’s goal will be to help you poop more regularly, manage your pain, and treat other digestive tract symptoms.

2. IBS-D

IBS-D means that you tend to have diarrhea when you’re experiencing IBS. Again, you should only consider the days when you actually have symptoms. You don’t have to monitor symptoms on days when your poop is normal.

IBS-C and IBS-D cause opposite symptoms. With IBS-D, on days you have symptoms, more than a quarter of your bowel movements will be watery or loose. On those same days, less than a quarter will be hard or lumpy.

Depending on the criteria used, either IBS-D or IBS-M may be the most common form. Different studies come up with different answers about which type is most common.

People living with IBS-D reported that their abdominal pain and sudden urges to use the bathroom were the symptoms that bothered them the most. About one-third of people with IBS-D report losing bowel control (fecal incontinence), especially during flare-ups. People with IBS-D report a lower quality of life than people with IBS-C.

People with IBS-D may be more likely to avoid food, certain foods, and some activities than those with IBS-C. It’s not known if this is connected to their pain levels, to the sudden urge to poop, or other factors.

There are some medications available as part of your treatment plan for IBS-D. Some are expensive and/or have serious potential side effects, which you can discuss with your doctor.

3. IBS-M

IBS-M stands for IBS with mixed bowel habits. If your doctor diagnoses you with this type, it means that you have some of the characteristics of IBS-C and some of IBS-D. Specifically, it means that, on days when your poop is affected by IBS, sometimes you have diarrhea, and sometimes you experience constipation. In fact, a quarter or more of your stools will be watery and loose, and a quarter or more will be lumpy and hard.

IBS-M isn’t just a “default” diagnosis if you don’t fit IBS-C or IBS-D. To meet IBS-M criteria, at least a quarter of your stools are hard/lumpy and at least a quarter are loose/watery on days with symptoms.

There’s not a lot of research specifically about IBS-M. When doctors give medications for IBS-M, they may have to pick which symptom they most want to treat: constipation, diarrhea, or abdominal pain. You may also have to take multiple medications if you want to try to treat all of the symptoms at once.

4. IBS-U

IBS-U is the unclassified form of IBS. This means that you meet the current diagnostic criteria, but your symptoms do not match any of the categories above. Not much is known about this type of IBS.

Even if a doctor can’t pinpoint the exact cause or type of IBS that you’re living with, they might be able to recommend changes to your diet that can help.

For example, a low-FODMAP diet may help between 50 percent and 80 percent of people living with IBS, regardless of type. FODMAPs are certain kinds of carbohydrates. The low-FODMAP diet usually requires you to eliminate these, then add them back in slowly to see if they trigger IBS symptoms. This is something that may be helpful, even if you don’t know what kind of IBS you have. Your doctor can send you to a registered dietitian if you need help understanding what foods to avoid. They can help you create a diet you’ll love that doesn’t include food that causes you problems.

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