It’s simple to tell when your gut isn’t working well — figuring out why can be trickier.
You may wonder whether you have irritable bowel syndrome (IBS) or small intestinal bacterial overgrowth (SIBO). Or, perhaps you have ulcerative colitis or Crohn’s disease.
These gut disorders are distinct conditions. Their symptoms often overlap — like abdominal pain, diarrhea, and an urgent need to run to the restroom.
Moreover, these digestive issues may also share some of the same underlying culprits. These could include parasites and an unhealthy gut microbiome. (1, 2)
Read on to understand the differences between IBS, SIBO, ulcerative colitis, and Crohn’s disease. Plus, discover hidden culprits of the conditions and what to do about them.
What Is Irritable Bowel Syndrome (IBS)?
IBS refers to chronic digestive issues that don’t have a clearly identifiable cause. It’s estimated to affect up to 15% of Americans. (3, 4)
Symptoms of IBS include unexplained chronic abdominal pain, along with irregular bowel habits. You may have diarrhea, constipation, or alternate between the two. (5)
Getting to a diagnosis of IBS isn’t a very straightforward path, though.
First, doctors typically rule out other possible conditions. For example, your doctor may test to see if you have ulcerative colitis, Crohn’s disease, or celiac disease. After likely causes of your symptoms are ruled out, your doctor may diagnose IBS.
Resolving IBS isn't straightforward either. That's because experts aren't sure what causes it. They’ve only identified factors that may predispose you to the condition. But, knowing risk factors for IBS may give you some clues for remedies.
Some risk factors for IBS include: (3, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Gender: IBS — particularly with constipation — is more common in women than in men. This may be related to sex hormone differences and genetic variations.
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Imbalanced gut neurotransmitters: Your gut produces nerve messengers — like serotonin and GABA — which could influence your gut symptoms. If your gut microbiome is in disarray, it impacts your production of these neurotransmitters.
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Microbiome imbalance: IBS is linked to a disruption in the composition of your gut microbiome. Scientists have found that specific problematic gut bacteria are more common in people with IBS. In some cases, these bugs may contribute to the condition.
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Previous gut infection: IBS may set in after food poisoning or drinking water tainted with parasites like giardia. Additionally, IBS may take root after a Clostridium difficile bacterial infection.
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SIBO: Not only is SIBO a gut issue on its own, but it may also contribute to IBS symptoms. Antibiotic use may increase your SIBO risk.
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Small intestinal fungal overgrowth (SIFO): This refers to the excess growth of fungi in your small intestine. A top culprit in SIFO is the yeast Candida albicans.
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Stress or trauma: These factors may not be the sole cause of IBS, but they may increase your risk of gut problems. Moreover, difficulty coping with stress may worsen IBS symptoms.
Among this list, an often overlooked factor in IBS is parasitic infections. Some parasites interfere with your gut motility, resulting in diarrhea or constipation. They may also trigger abdominal pain, bloating, and neurotransmitter imbalance. (22, 23)
If your attempts to fix IBS have fallen short, you are well-advised to consider whether you might have a chronic parasite infection.
As scientists continue to unravel the “mystery” of what causes IBS, keep the above list of risk factors in mind. Addressing parasites and other potential culprits may help you conquer the condition.
What Is Small Intestinal Bacterial Overgrowth (SIBO)?

SIBO is when bacteria from your large intestine migrate into your small intestine. As a result, there are more microbes in your small intestine than there should be. This includes strains of bacteria not typically found in your small intestine. (24)
Symptoms of SIBO include abdominal bloating, pain, excess gas, and diarrhea. The condition may also interfere with your absorption of nutrients. (25)
The gas and bloating come from microbes fermenting carbohydrates in your gut. You exhale some of this gas through your lungs. Doctors can measure this gas through specialized breath testing. This is used to help diagnose SIBO. (26)
So, what enables gut bacteria to travel and multiply where they shouldn’t? That's covered next.
Gut valve malfunction and SIBO
Between your small and large intestine is the ileocecal valve. It controls the movement of materials between these two parts of your gut.
But, sometimes, the ileocecal valve malfunctions. This could happen for different reasons. One might be parasites. (27)
Parasites hanging out near your ileocecal valve may prevent it from closing. Parasitic worms like ascaris and anisakis tend to migrate to this area of your gut. They could physically obstruct the valve area or cause swelling that prevents it from shutting. (28, 29)
You can likely guess why this could lead to problems.
If your ileocecal valve is stuck open, your large intestine contents can leak back into your small intestine. This includes unwelcome bacteria.
The rogue bacteria can rob you of nutrients. Over time, this can potentially lead you to develop nutritional deficiencies. The microbes may also release toxins and trigger gut inflammation. (24)
Liver health and SIBO risk

Your liver may not be the first thing you connect with SIBO. Yet, it has important links to an increased risk of the condition.
People with liver cirrhosis — extensive scarring — tend to have slower gut motility. This means your gut contents sit in the small intestine longer. That gives microbes more time to feed on nutrients in your gut and multiply in number. In other words, they overgrow. (30, 31)
One study found that nearly half of people with liver cirrhosis had SIBO, compared to less than 10% of otherwise healthy people. (30)
Poor liver health may also lead to backed-up bile ducts. When your bile ducts are clogged, less bile gets into your small intestine. Lower levels of bile in your gut are linked to bacterial overgrowth. That could be because bile has anti-microbial properties. (32)
Additionally, parasites can interfere with your liver health by clogging your bile ducts. For example, Ascaris lumbricoides roundworms and fasciola flukes have commonly been found in bile ducts. (33, 34)
To recap, poor liver health and parasites can slow your gut motility and reduce bile levels in your gut. That may increase your risk of SIBO.
Other SIBO risk factors
Many other factors can affect your chance of SIBO. These include your diet, medication usage, and several disease conditions.
If your diet is high in sugar and other refined carbs, your risk of SIBO may increase. Sugar can shift the balance of your gut microbiome. It favors the overgrowth of harmful bacteria and fungi like candida. (35, 36)
Additionally, if you take heartburn drugs that reduce stomach acid, your risk of SIBO increases. Frequent antibiotic use may also boost your chance of SIBO. (37, 38)
Low thyroid function or hypothyroidism has been linked to increased SIBO risk as well. But, research suggests that this increased risk may stem from taking levothyroxine. That’s a synthetic (human-made) thyroid medicine. (39, 40)
Some of the other disorders that may increase your risk of SIBO include: (39, 41, 42, 43)
- Crohn’s disease
- Celiac disease
- Diabetes
- Gastroparesis (slow stomach emptying)
- Parkinson’s disease
- Scleroderma (an autoimmune disease)
- Chronic pancreatitis
All these diseases can impact your digestive tract. They may slow it down and prevent your ileocecal valve from working correctly.
What Is Ulcerative Colitis?

The term colitis is sometimes used loosely. For example, some people may use “colitis” to refer to IBS. But, that’s technically not the correct usage of the term.
Ulcerative colitis is not IBS. Ulcerative colitis is one of the two main types of inflammatory bowel disease (IBD). Crohn’s disease is the other main type. These chronic diseases both cause severe gut inflammation. Symptoms can flare up and subside in cycles that may last for weeks or months. (44, 45)
Here’s a closer look at ulcerative colitis.
Symptoms and risk factors of ulcerative colitis
Ulcerative colitis affects your large intestine — also called the colon. Ulcers (sores) develop on your colon’s innermost lining. These ulcers generate pus and mucus. This leads to gut pain and urgent, loose bowel movements. The ulcers also make your stools bloody. (44, 46)
Bloody poop is a tell-tale sign of problems beyond IBS. A digestive health doctor may test your blood and stool for signs of IBD. Your doctor may also do tests — endoscopies and a CT scan — to see what’s going on inside your digestive tract.
Though ulcerative colitis is a well-known disease, experts aren’t sure what causes it. Certain factors may increase your risk. These include: (44, 46, 47, 48)
- Genetics
- Overactive intestinal immune system
- Poor gut microbiome health
Additionally, an inflammatory environment in your gut can leave you open to infections. This includes candida. Overgrowth of this yeast may make it harder to heal from ulcerative colitis. (49)
Drugs, including steroid medications, are often used to help calm the immune system and reduce IBD inflammation. These drugs can have many side effects, such as weight gain and an increased chance of infections. (44, 45)
So, think about whether there’s an underlying factor in your ulcerative colitis that could be resolved. That includes considering parasites.
Parasites or ulcerative colitis?
In some cases, parasitic infections have been misdiagnosed as ulcerative colitis.
In one case study, a man thought to have ulcerative colitis actually had a giardia parasite infection. This critter is known for causing diarrhea and abdominal cramps. (50, 51)
Another study looked at six men with ulcerative colitis who weren’t getting better with standard medical treatment. It turns out they were infected with the microscopic parasite Blastocystis hominis, which can cause diarrhea. All men recovered in about three weeks when treated for the parasite. (52, 53)
Other human studies have found that strongyloides parasite infections often mimic ulcerative colitis. That nasty roundworm can cause abdominal pain, bloating, heartburn, diarrhea, and constipation. (54, 55, 56)
It’s tough to get well when the culprit is overlooked. Remember that parasites are a possible cause of ulcerative colitis-like symptoms.
What Is Crohn’s Disease?
Crohn’s disease is the other major disorder under the IBD umbrella. Similar to ulcerative colitis, Crohn’s disease can cause severe inflammation and sores in your digestive tract. This can result in abdominal pain and diarrhea, which can be bloody. (45)
However, there are distinct differences between the two main types of IBD. Read on to see how they compare.
Crohn’s disease vs. ulcerative colitis
To understand the difference between Crohn’s disease and ulcerative colitis, consider these key factors: (44, 45)
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What’s affected: Ulcerative colitis only affects the large intestine. Crohn’s disease can affect any part of your digestive tract. This includes everything from your mouth to your anus. For example, in some cases, it affects your stomach, causing nausea.
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Main target in your gut: Crohn’s disease most commonly affects the last part of your small intestine and the first part of your large intestine. Ulcerative colitis can affect your entire large intestine, including the end portion called the rectum.
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Spotty occurrence: The portions of the intestines that Crohn’s disease impacts can be spotty. It may affect some parts but skip adjacent areas. The inflammation of ulcerative colitis doesn’t skip nearby patches of your intestines.
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How deep it goes: The damage of Crohn’s disease can go all the way through your gut wall. In contrast, ulcerative colitis only affects the innermost lining of your colon. It doesn’t go deep into the wall of your gut.
Risk factors and causes of Crohn’s disease
Like ulcerative colitis, it’s uncertain what causes Crohn’s disease. They share similar risk factors. These include genetics, an overactive immune system, and disrupted microbiome health. In addition, smoking is a risk factor for Crohn’s disease. (45)
The yeast Candida albicans might also play a role in Crohn’s disease. People with Crohn’s disease more commonly have an overgrowth of candida in their gut compared to healthy people. Overgrowth of the yeast may trigger gut inflammation. (57)
And, sometimes, Crohn’s disease is a case of mistaken identity.
Certain parasitic infections may be misdiagnosed as Crohn’s disease. This was found in a case of Entamoeba histolytica. That’s a one-celled parasite that can cause loose stools, stomach pain, and stomach cramps. (58, 59)
In another case, a person infected with pinworms was initially misdiagnosed with Crohn’s disease. The pinworms were Enterobius vermicularis and can cause gut pain and diarrhea. They’re the most common cause of parasitic worm (helminth) infections in the United States. (60)
So remember, when you have a longstanding gut issue you can't seem to resolve, consider: Could it be parasites?
How to Fix Your Gut Issues

No matter which bowel condition you might have — such as IBS or ulcerative colitis — there is hope.
Generally, the solution requires removing toxins and treating chronic infections. Dietary and lifestyle changes may help, too.
Consider the following strategies to help you get a handle on your gut issues:
1. Support drainage and detox
Good drainage is essential for ridding your body of toxins that can compromise gut health. An unhealthy gut that’s burdened with contaminants could become a stagnant breeding ground for pathogens.
Ways to support drainage and toxin removal, as well as gut health, include: (61,
62, 63, 64, 65, 66, 67)
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Binders: Binders can help sponge up toxins. They haul out the garbage and give you additional support for your gut.
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Constipation support: Constipation is often involved in IBS. At a minimum, you need to poop daily to eliminate toxins. And pooping 2–3 times a day is best during detox. Certain herbs support regular elimination.
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Good bile flow: Bile is a primary route for eliminating toxins via your stools. Good bile flow may also reduce SIBO risk.
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Liver-supportive herbs: Liver inflammation often accompanies gut disorders. Herbs that support your liver function may help ease the inflammation of this organ.
2. Treat parasites and other chronic infections
As mentioned above, parasites and candida overgrowth sometimes are at the root of gut conditions. In fact, sometimes gut issues are misdiagnosed as IBD when they’re really parasite infections.
You can fight back against parasites with immune-supportive herbs. (68, 69, 70, 71, 72)
Additionally, you can use certain essential oils to help you get rid of parasites. (73, 74)
Finally, if candida overgrowth is contributing to your gut issues, consider a candida cleanse. That may help reduce the burden on your digestive tract.
3. Move your body

You already know physical activity is essential for good health. It may have bonus benefits when you’re trying to overcome parasite and gut problems.
In studies of people with bowel diseases, participants have reported that regular physical activity helped: (75)
- Decrease stress
- Improve sleep
- Lift mood
Physical activity may also help bolster your immune system to fight parasites, as well as help you get rid of toxins. (76)
Movement is essential for draining your body’s lymph, which collects toxins. Without regular physical activity, toxins can build up in your lymphatic system. (77, 78)
But, what if you’re avoiding physical activity because you aren't sure how your gut will respond?
Start small. Do whatever physical activity you’re comfortable doing. Any movement is better than none. If you don’t move, your lymph can’t move.
Notably, you can also take herbal blends designed to support your lymphatic system. (77, 78, 79)
4. Change your diet
Following a Western-style diet rich in animal protein and refined carbs but low in fiber could be bad news for your gut. These dietary factors are linked with poor gut microbiome health and increased risk of digestive disorders. (80)
Refined carbs like sugar increase inflammation. This may worsen gut conditions like IBD and SIBO. Moreover, sugar may help candida, parasites, and unwelcome bacteria multiply. (36, 81, 82, 83)
So, check your diet for hidden sugars that could be adding to your digestive woes.
You may also find it helpful to avoid gluten — a protein in wheat, barley, and rye. Gluten can increase intestinal permeability or “leaky gut.” This contributes to digestive health problems. (84, 85)
Additionally, a diet low in FODMAPS (fermentable carbohydrates) may help ease the symptoms of some bowel disorders. Just remember, it is a temporary way to relieve symptoms. It’s not a long-term solution. Low-FODMAP diets tend to be inadequate in fiber. (86, 87)
Plant-based diets rich in fiber are linked with an increased diversity in your microbiome. A diverse microbiome is a healthy one. (80)
If you’ve been on a relatively low-fiber diet, increase your fiber intake gradually — not all at once. You have to give your gut time to adjust. Fiber adds bulk to your stools. This can help regulate your bowel movements. (88)
However, if you're having a flare-up of ulcerative colitis symptoms, you may need to restrict your fiber intake for the time being. Tailor your diet to your individual needs and tolerances. (44)
Lastly, consider reducing or avoiding alcohol intake, at least during healing. In studies, alcohol seems to be a contributor to SIBO and IBDs like ulcerative colitis. Alcohol can also increase intestinal permeability or “leaky gut.” (30, 89, 90)
Addressing these factors could help put you back on the path to a full and healthy life — where finding the nearest restroom is no longer top of mind.
Bowel Disease to Bowel EASE
Resolving gut disorders starts with getting to the root of the problem. This is true whether you’ve received a diagnosis of IBS, SIBO, Crohn’s disease, or ulcerative colitis.
Several factors can contribute to your risk of these conditions — many of which you can control. You can kick out parasites, change your diet, and boost your drainage and detox. These factors are often hidden culprits in gut issues.
Dietary herbal support and binders could all aid your gut health. A healthy diet low in sugar and regular physical activity could help as well.
Armed with these cutting-edge approaches, you can heal your gut. What would your life look like if your bowel issues were gone?