What are the Most Common Symptoms of SIBO?

SIBO or Small Intestinal Bacterial Overgrowth is the most common problem many people are having these days. But, most people don't know they actually have SIBO as its symptoms are very common ones like diarrhea, constipation, etc… However, SIBO, when left undiagnosed and untreated, may lead to more serious health issues. 

So, it is very important to know if you have SIBO related problems by being aware of its symptoms and getting it treated as soon as possible. 

SIBO symptoms


This article will help you know what SIBO is and what are the most common symptoms of SIBO so that you can identify it earlier and treat it earlier. 

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What is SIBO?

SIBO or Small Intestinal Bacterial Overgrowth occurs when wrong bacterial species grow in large amounts in the small intestine. These bacteria will be usually found in other parts of the intestinal tract like the large intestine in small amounts and will be balanced or eliminated regularly. When these bacteria overgrow in the small intestine, it causes various gut problems. 


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Symptoms of SIBO

With SIBO, the abnormal bacterial growth in the small intestine will start triggering a whole lot of gut-related symptoms causing discomfort and health issues in our body. Most times,  these symptoms seem very similar to the symptoms of IBS or Irritable Bowel Syndrome. 

Here I have listed the most common symptoms of SIBO that you must keep an eye on.  


When there is excess gas formed in your intestine, it can sometimes be very uncomfortable. Excess gas, flatulence, or windy feeling can be caused by a variety of reasons and some of which may not be associated with any serious disorders. 

However, excess gas can be one of the prominent symptoms of the SIBO problem. With SIBO, the excess bacteria can disturb the regular intestinal function. These bacteria may absorb the necessary nutrients and result in abnormal fermentation and digestion processes.

Because of this excess gas can be formed in the digestive tract which can be uncomfortable and sometimes painful. Most people with SIBO will complain of frequent passing of gas, and especially if the gas is foul-smelling then it is definitely because of SIBO as this is because of abnormal fermentation by the bad bacteria. 

SIBO symptoms - Gas or bloating



Bloating is one of the popular symptoms of SIBO. When your gut is filled with gas or air, you get a feeling that your stomach is full or swollen. This is what is called bloating. Your abdomen may be distended, hard, and, sometimes, painful. Mostly, bloating is accompanied by flatulence, burping, or abdominal rumbling which eventually disturbs day-to-day activities. 

Several females will complain that they look like they are pregnant, while in reality, it is the SIBO that is causing them to look that way. 

When you have SIBO issues, the overgrown bacteria may absorb the nutrients in your body and release unwanted gases to the system. This eventually causes gas buildup and hence, bloating occurs.


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Constipation is one of the symptoms of SIBO that is very often mistaken as it is because of IBS ( Irritable Bowel Syndrome). Constipation is nothing but, fewer bowel movements accompanied by dry, hard stools and pain. Most people will feel that less number of bowel movements are completely normal, but in reality, if you are not having at least one bowel movement a day that is constipation. 

As said previously, the overgrown gut microbes that feed on your body nutrient and release gases tend to interfere in the regular transit of food and waste through the gastrointestinal tract. 

When the transit time reduces, the wastes accumulate and cause constipation. The problem with constipation is that this enables the bacteria to grow more and eventually causes a vicious cycle of SIBO.

Now there are two different kinds of SIBO, one hydrogen, and the other methane. Methane predominant SIBO especially causes constipation. 

SIBO basically interferes with the peristalsis movement on your gut, and when that interferes it leads to constipation. 


SIBO symptoms - constipation


Just like constipation, the gut microbe imbalance can easily be characterized by diarrhea, the occurrence of frequent loose and watery stools. 

Because of the foreign microbes that interfere with regular bowel movements, the intestine may be affected and abnormal water secretion may happen. This ultimately results in diarrhea. Diarrhea in SIBO varies from loose stools to all the way watery stools.

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Abdominal cramps and pain

Abdominal cramps and pain can range from being trivial to life-threatening. Abdominal pain is often accompanied by vomiting, diarrhea, or constipation. 

When someone has SIBO, the excess foreign microbe in the small intestine may trigger unwanted reactions in it. This may be characterized by cramps or pain.

SIBO symptoms - fatigue


This is one of the most common symptoms of SIBO. But this is often ignored by most people. Fatigue is sometimes accompanied by brain fog and dizziness. 

Since the SIBO condition disturbs proper digestion, nutrients from the food are not properly absorbed by the body. The bacteria even use up some nutrients to grow further disturbing the body's functions. This causes Vitamin B12 deficiency, fat malabsorption, fat-soluble vitamin deficiency, and protein malabsorption. All these problems eventually contribute to fatigue and dizziness.

Related article - Do you have SIBO fatigue?

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Unexpected weight loss

As said, SIBO can cause nutritional deficiency as most of the nutrients are absorbed by the excess bacteria. This may result in malnutrition characterized by sudden weight loss. To overcome this, doctors may mostly advise a Low FODMAP diet which helps in weight gain.



SIBO also can lead to symptoms of anxiety and depression.  Several people have been on psychiatric medications for several years and the underlying problem for them is actually  SIBO.  

There is a strong connection between gut health and brain health.  New research points out that when there is a gut dysfunction specially overgrowth of certain bacteria that leads to anxiety, depression, and mood changes.  

What people do not know is that brain chemicals like serotonin and dopamine are also present in the gut.  And as SIBO causes high inflammation in the gut, that leads to an imbalance of these chemicals and triggers anxiety and depression. 

SIBO symptoms- depression

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Skin disorder

Several people with SIBO also have various skin conditions like Eczema, hives, random reactions to food and things around them. They would have seen several skin doctors and tried several creams but still, they may not get better because the real reason is the underlying inflammation in the gut.  Once the SIBO is improved the skin health also improves for these people. 


So, these are the most common symptoms that characterize the case of Small Intestine Bacterial Overgrowth or SIBO. When you feel like your body shows any or many of these symptoms it is better to consult a doctor and test for SIBO. 

With proper diet and holistic treatment, the SIBO condition can easily be treated.


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