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Russell Havranek, MD
Gastroenterologist in San Antonio, TX

SIBO Specialist

As a leading gastroenterologist in San Antonio, Dr. Havranek is an expert in diagnosing and testing for Small Intestinal Bacterial Overgrowth (SIBO). If you experience symptoms like bloating after eating certain foods or abdominal discomfort, you should be evaluated for SIBO. Call or click on the appointment request button below to schedule a consult with Dr. Havranek.


SIBO, or Small Intestinal Bacterial Overgrowth, is defined as an increase in the number of bacteria in your small intestine from 1000 to 100,000 or more and/or changes in the types of bacteria present in the small intestine.  Normally, your small bowel is relatively sterile with very low levels of bacteria while the colon is full of bacteria.

There are many conditions that put you at risk for SIBO and when this happens you get large overgrowth of bacteria from the colon into the small bowel where they don’t belong.  When you get this altered small bowel bacterial flora they tend to ferment the foods that you eat and effect the motility of the small bowel.  This process causes a lot of gastrointestinal distress and can be destructive to your digestive health.


The symptoms are some of the most common gastrointestinal symptoms people see their doctor for.  They also mimic many of the symptoms of IBS (irritable bowel syndrome) and many patients are misdiagnosed.  The most common symptoms for SIBO are:


SIBO causes in San Antonio, TXThe causes of SIBO can be quite complex and often differs between individuals.  There are many risk factors like medications, antibiotics, prior abdominal operations, diverticular disease and some chronic medical illnesses, just to name a few.  Normally, food is propelled from the stomach through the small bowel and into the colon by muscle contractions in the bowel.  This action also moves the bacteria along into the colon, which limits the number of bacteria in the small bowel.  When this muscular action does not occur as it is supposed to it can allow the bacteria to move back into the small bowel from the colon.  With the slowed motility of the small bowel the environment turns from mostly sterile to stagnant, which is ideal for bacteria to remain and grow.  When this happens you now have SIBO.


SIBO is largely under-diagnosed and the symptoms it causes just written off as IBS.  This is because many people in San Antonio, TX don’t seek medical care for their Small Intestinal Bacterial Overgrowth symptoms and because many doctors aren’t aware of how common this condition is.

Diagnosis of SIBO is simple and painless.  Since the bacteria in the small bowel ferment foods and produce gas, we use this to find them.  Using what is called a SIBO breath test, patients with suspected SIBO are given a sugar like solution (lactulose) to drink then over the course of 90 minutes or so they blow in a tube every 15 minutes.  If SIBO is present, the increased levels of bacterial will ferment the lactulose and produce gas, which safely moves from the bowel into the lungs through the blood vessels.  Then when they blow in the machine it detects the presence or absence of this gas to make the diagnosis.

The breath test is a very easy test that I regularly perform in my office and generally takes about 90 minutes to complete.  The cost of the breath test is covered by most third party insurance providers and is generally just the office visit copay.  Since the type of insurance you have dictates coverage, please check with your insurance provider to confirm rates & coverage and if you need additional assistance my office staff would be happy to help as well.


Treatment consists of both eradication of the bacteria and diet/ lifestyle changes.  Bacteria love to feast on and ferment carbohydrates.  Because of this we focus on low carb diets and avoidance of FODMAPs foods to help reduce symptoms.  If we don’t give the bacteria as much of this stuff to ferment, they make less gas and symptoms are improved.  The other focus is eradication of the bacterial themselves.

There are two main ways I approach this.  One option is antibiotics.  There are some antibiotics that have very good activity against Small Intestinal Bacterial Overgrowth with relatively few potential side effects.  Sometimes they are covered by your health insurance and sometimes they are not.  We have some generic antibiotic options that are cheaper but don’t work near as well in my experience.  One of my favorite treatments is a natural product developed by a prominent gastroenterologist in Dallas, TX and available online without a prescription.  It’s called Atrantil, and it uses natural products that have activity against the bacterial in our small bowel without the use of antibiotics.

SIBO is common, the symptoms can be debilitating and the condition is treatable.  If you suffer from symptoms of SIBO, contact your physician or click on the appointment link below and I will be happy to help.  I hope this information was useful, have a great day.