Worried If It’s IBS… Or Something Else? Some Quick Answers

If you’re having IBS (irritable bowel syndrome) symptoms like constipation and diarrhoea, you might be wondering what’s wrong with you. Irritable bowel syndrome can seriously impact your life. If you’ve been told it’s ‘just’ IBS, or suspect you have it, read on to find out what could be going on.

Quick answers

  • IBS isn’t a disease. It’s a set of symptoms.
  • The reason you have IBS symptoms is highly individual, and hard to ‘prove’.
  • IBS symptoms are also the symptoms of many diseases, both serious and not-so-serious.
  • It’s important to rule out serious diseases that need swift medical attention. Always tell your doctor if you have IBS symptoms.
  • Mounting research has shown an undeniable link between IBS symptoms and dysbiosis: an imbalance of the communities of microbes in your gut.
  • Modern, high-stress lifestyles with bad diets and over-use of antibiotics encourage dysbiosis. 
  • Addressing your diet and lifestyle, along with using targeted supplements, can help reverse dysbiosis and tackle your IBS symptoms.

What can be mistaken for IBS?

There are some serious medical conditions that share the same symptoms as IBS.

However, IBS symptoms are unlikely to indicate a serious disease. 

IBS symptoms can also accompany other symptoms, like nausea or vomiting. You can learn more about nausea and IBS on our blog Is nausea a symptom of IBS?

IBS is a tricky thing to define, because it’s not a disease: it’s a set of symptoms. Because constipation, diarrhoea and bloating are the symptoms of so many diseases—both serious and not so serious—IBS symptoms could indicate an almost infinite number of conditions.

If you have IBS symptoms and you want to investigate what else it might be, our symptom checker is a good place to start.

According to BUPA UK, one in five people in the UK have IBS. 

IBS is often called a ‘diagnosis of exclusion’ [Source: PubMed]. That means that if a doctor can’t find any evidence that you’re suffering from a disease with a known cause, they could diagnose you with IBS.

If you’ve been diagnosed with IBS, while it’s great news that you aren’t suffering from anything more serious, you’ve still got your symptoms to deal with. And as anyone with IBS knows, they can really ruin your fun.

On top of dealing with your symptoms, you might be wondering why you have them, and how you can be free of them. You might have been told that IBS is ‘just something you’ll have to live with’.

The truth is, there’s a lot you can do to reveal the potential causes of your IBS, and a lot you can do to get better. But first, let’s look at some of the more serious diseases that can be confused with IBS.

Find the reasons for your IBS symptoms.

View our gut health tests

Serious diseases that can be mistaken for IBS 

Crohn’s disease

Crohn’s disease is a type of inflammatory bowel disease (IBD). We don’t yet know precisely why, but the immune system of someone with Crohn’s disease attacks the lining and tissues of their gut as if it’s a foreign invader, like a virus or pathogenic bacteria [Source: PubMed]. According to the NHS, the most common symptoms are:

  • diarrhoea
  • stomach aches and cramps
  • blood in your stools
  • fatigue
  • weight loss

Having blood in your stools is not a symptom of IBS. If you have blood in your stools, you should always tell your doctor, who can test for IBD. It’s also possible you could have haemorrhoids or a tear in your rectum, which are more common causes of blood in your stools.

Ulcerative colitis

Ulcerative colitis is another type of IBD. It’s very similar to Crohn’s disease. The main difference is that Ulcerative colitis only affects the colon, while Crohn’s disease can affect any part of the digestive tract from the mouth to the anus.

Coeliac Disease

Coeliac disease is an auto-immune disorder caused by gluten in barley, rye, and wheat [Source: PubMed]. Diarrhoea is usually the main symptom. It can also cause vomiting and weight loss. 

The resulting inflammation and nutrient deficiencies of coeliac disease can cause anaemia, bone or joint pain, seizures, and skin rashes [Source: PubMed].

Cancers of the gastrointestinal tract

There are many types of cancer that can cause a few of the same symptoms as IBS. Your doctor can test to rule these out. The most common is colon cancer, which can cause bleeding, blood in your stools, and weight loss.

Women need to be aware that ovarian cancer—like IBS—can cause bloating, appetite loss and lack of energy. These symptoms might not happen until the advanced stages, so if you have severe bloating that doesn’t respond to changes in your diet, tell your doctor.


Your pancreas sits behind your stomach. It releases juices that help you to digest your food.

The symptoms of acute pancreatitis are similar to IBS. 

They include:

  • severe pain in your gut
  • nausea
  • diarrhoea

However, pancreatitis also can cause:

  • fever
  • jaundice (yellow skin and eyes)
  • a racing heartbeat

Acute pancreatitis usually gets better in about a week, but it can turn into chronic pancreatitis, where inflammation has damaged the pancreas and it no longer works properly.

Do gut bacteria cause IBS?

The bacteria and other microbes in your gut are strongly linked to IBS symptoms [Source: PubMed]. 

While we can’t yet prove beyond doubt that your gut bacteria are causing your IBS symptoms, countless studies have shown that people with IBS symptoms are far more likely to have dysbiosis than people with no IBS symptoms.

If you’d like to learn more about the inextricable link between IBS symptoms and dysbiosis, check out our blog Irritable bowel syndrome: how can the NHS help?

Dysbiosis is an imbalance of the communities of bacteria and other microbes that live in your gut. There are over 1000 different types of them, and in an ideal world, they all live together in harmony, each one doing important work to keep you healthy.

Your collection of gut microbes—known as your microbiome—is as unique as your fingerprint. While two very different microbiomes can both be healthy, there’s one thing that all the best microbiomes have in common: diversity.

A lack of diversity is the hallmark of dysbiosis [Source: PubMed]. And if you’ve got IBS symptoms, you’re very likely to have dysbiosis. In a study [Source: PubMed] conducted in Sweden, Norway, Denmark, and Spain, on patients between 17 and 76 years old, 73% of IBS patients had dysbiosis, while only 16% of healthy individuals had dysbiosis.

The good news is that you definitely don’t have to live with dysbiosis. It might take a bit of time and work, but diet and lifestyle have a massive impact on your microbiome [Source: PubMed]. There are also many supplements and herbs that have been proven in research to shape and change the microbiome.

Dysbiosis comes in many forms. Let’s take a look at some of the different ways your microbiome can get off track.

Large intestinal dysbiosis

The vast majority of your bacteria and other microbes live in your large intestine: scientists have measured up to 10,000,000,000 per millilitre of fluid there. You also have microbes in your small intestine: around 10,000 per millilitre of fluid, and even fewer in your stomach [Source: PubMed].

While some microbes can be classed as ‘good’ or ‘bad’, in reality, it’s much more complex than that. A microbiome is an ecosystem, so just like a national park or a coral reef, it’s all about the balance between the many species that live there [Source: PubMed].

What causes dysbiosis?

Many things can cause dysbiosis. Here are some of the most common:


Research has revealed that antibiotics can cut the number of microbial species in your gut down to one tenth of the previous level. Not by one tenth, to one tenth: that’s a 90 percent reduction [Source: PubMed].


That fight-or-flight response that you need for dealing with short-term danger—like running away from an attacker—is very useful for imminent danger, but harmful for long-term stress, like worrying about your children, or work. You may suffer from chronic stress, which means stress hormones are constantly pumping round your body, reducing diversity in your microbiome [Source: PubMed]. 

To compound the situation, that altered gut microbial population then affects the regulation of neurotransmitters, intensifying stress further [Source: PubMed].

Typical western diet: high in processed foods and low in fibre

A diet full of whole plant foods is your best bet for microbial diversity [Source: PubMed]. A recent study compared the intestinal microbes of young villagers in Burkina Faso, Africa, with those of children in Florence, Italy. The African villagers with a diet of whole, fermented grains had far higher microbial diversity than the Italians, who ate a ‘normal’ Western diet, heavy on processed foods and sugars [Source: PubMed].

To boost your fibre intake, eat as many high-fibre foods every day as you can. For example:

  • raspberries
  • strawberries
  • pears
  • chickpeas
  • lentils
  • avocado
  • oats
  • almonds

(Added 8/4/2021)


PPIs (proton pump inhibitors)—often used for reflux and heartburn—have been found to negatively affect the gut microbiome the most, along with anti-psychotic medications, laxatives and NSAIDs (non-steroidal anti-inflammatory drugs) [Source: PubMed].

In all these examples, opportunistic bacteria, yeasts and viruses can take over and reduce diversity. Because some types of microbes are more pushy than others, if they get a chance to dominate, they’ll take it. They were probably always there in your gut, but in a less than ideal environment, they can multiply and take charge [Source: PubMed].

Speak to an expert. Free gut health consultation.


Types of Intestinal Dysbiosis

There are three main types of large intestinal dysbiosis:

  1. Loss of beneficial microbes
  2. Overgrowth of potentially bad microbes
  3. Loss of diversity [Source: PubMed]

They can, and often do, exist together. All of our Gut Health Tests reveal your levels of beneficial microbes, and whether or not your potentially pathogenic microbes are in check. They also analyse how diverse your microbiome is by looking at your levels of specific species and types of bacteria.

Almost all of us today have some level of dysbiosis [Source: PubMed]. If you want to get great gut health, check out our Gut Health Program: a 12-week course guided by Registered Nutritional Therapists and Functional Medicine Practitioners.


SIBO stands for small intestinal bacterial overgrowth. Like it sounds, if you have SIBO, you have an imbalance of bacteria in your small intestine [Source: PubMed].

Usually, that means your small intestine contains too many bacteria. But as research into SIBO continues, we’re finding out that at least some cases of SIBO are down to a dysbiosis of the communities of bacteria in the small intestine. In other words, you can have an imbalance of bacteria there, but normal numbers [Source: PubMed].

Your large intestine houses the vast majority of the microbes in your gut. The small intestine is home to far fewer, but sometimes, too many set up shop there, or the delicate balance of the small intestinal ecosystem gets disrupted.

Upto 85% of people with IBS symptoms have been found to have SIBO [Source: PubMed]. For a long time, the NHS only tested for SIBO in a few, rare circumstances. Now, more and more NHS trusts are testing people with IBS symptoms for SIBO.

For all you need to know about SIBO, read our blog SIBO symptoms: what they mean, and what to do next.

If you think you might have SIBO, you can take an at-home SIBO test.


If you’ve got parasites living in your gut, you’re likely to have IBS symptoms like bloating, constipation and diarrhoea. However, some people can have parasites and have no symptoms at all [Source: PubMed].

The NHS tests for parasites, but they use a method that can sometimes miss the evidence that parasites are present. Our Gut Health Tests use PCR technology, which is much more sensitive.

To learn more about parasites, which ones we test for and why, read our blog Parasite testing | What you need to know


How do you tell if you have IBS or something else?

You can ask your doctor to rule out the following more serious conditions with tests:

IBD: Faecal calprotectin

  • Faecal calprotectin is a marker of inflammation in the gut.
  • In IBD, white blood cells rush to the area of inflammation and release calprotectin, among other chemicals.
  • Your levels of faecal calprotectin are a good indication of whether your IBS symptoms are in fact a sign of IBD.

Bowel cancer: stool test

  • If a doctor wants to rule out or check for bowel cancer, they are likely to give you a stool test.
  • After you’ve given a sample of your stool, your doctor will send it to a lab to screen it for traces of blood.
  • Even if it’s positive, bowel cancer is an uncommon reason for blood in your stool. You’re more likely to have a tear in the lining of your rectum, and/or haemorrhoids.
  • Your doctor may refer you to a specialist who can investigate further. NHS gastroenterologists use a colonoscopy or a colonography to look for evidence of bowel cancer. 

Ovarian cancer: blood test (CA125 test)

  • If your doctor thinks your symptoms could be due to ovarian cancer, you’ll probably get a blood test to check for CA125: a substance produced by some ovarian cancers. 
  • Even if you do have a high CA125 level, you don’t necessarily have cancer. 
  • There are lots of other conditions that can produce the same results, like endometriosis or fibroids.

Coeliac disease: blood test or biopsy

  • Blood tests and biopsies are the most common ways to test for coeliac disease. 
  • If your doctor suspects you have coeliac disease, they’re likely to give you a blood test first. However not everyone with coeliac disease will get a positive blood test.
  • For a biopsy, a gastroenterologist uses a procedure called an endoscopy, where they pass a thin tube down your throat to  take tiny samples of the lining of your small intestine. 

Pancreatitis: blood test and/or CT scan

  • If you’re showing signs of pancreatitis, your doctor may do a blood test and sometimes a CT scan to investigate further.
  • In the CT scan for pancreatitis, a doctor will take a series of X-rays to build up a more detailed image of your pancreas.

Find the reasons for your IBS symptoms.

View our gut health tests

Can IBS be misdiagnosed?

Because IBS is not a disease, it’s not really possible to diagnose it at all. Which means that technically, it’s not possible to misdiagnose it either.

However, millions of people in the UK are suffering with symptoms of IBS. If you’ve had diarrhoea, constipation or bloating for over six weeks, you fit the criteria for IBS.

Some specialists say that IBS can exist alongside more serious diseases, like IBD or coeliac disease, while others say that it’s the serious disease that produces those symptoms, so you can’t have both.

The biggest problem with ‘diagnosing’ yourself with IBS is that you might then mistakenly ‘accept’ that you have an incurable disease that you have to live with. This is absolutely untrue.

The evidence is now undeniable that IBS symptoms are linked to changes in your microbiome: dysbiosis. Balancing your microbiome can, and often does, have a massive impact on IBS symptoms.

Key takeaways

  • IBS isn’t a disease. It’s a set of symptoms.
  • The reason you have IBS symptoms is highly individual, and hard to ‘prove’.
  • IBS symptoms are also the symptoms of many diseases, both serious and not-so-serious.
  • It’s important to rule out serious diseases that need swift medical attention. Always tell your doctor if you have IBS symptoms.
  • Mounting research has shown an undeniable link between IBS symptoms and dysbiosis: an imbalance of the communities of microbes in your gut.
  • Modern, high-stress lifestyles with bad diets and over-use of antibiotics encourage dysbiosis. 
  • Addressing your diet and lifestyle, along with using targeted supplements, can help reverse dysbiosis and tackle your IBS symptoms.


Alexandra Falconer MA (Dist) DipCNM mBANT is a Registered Nutritional Therapist specialising in IBS and related conditions. A graduate of Brighton’s College of Naturopathic Medicine, she is committed to fighting the root causes of chronic illness and bringing functional medicine to everyone who needs it.

Before her natural health career, Alex was a journalist and copywriter. She continues to write for magazines and media agencies, and now combines her two great passions—writing and health—by creating content that empowers people to claim their right to a healthy body and mind.


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