Oregano oil is one of the best antimicrobials for SIBO but taking oregano oil for SIBO can also result in an uncomfortable die-off reactions that must be handled appropriately. The best herbal antimicrobials for SIBO include:
• Berberine
• Neem
• Allicin
• Oregano oil
• Thyme
• Cinnamon
When these antimicrobial herbs are used, such as oregano oil for SIBO, die-off reactions can occur. Thus it is important to use the correct dosage to combat small intestine bacterial overgrowth. Handling die-off reactions from SIBO can be challenging, so it is best to start low and increase to the recommended range on the bottle or by a qualified SIBO practitioner.
Many practitioners will use a breath test to confirm SIBO and then implement a SIBO treatment plan that involves the use of pharmaceutical antibiotics or herbal antimicrobials to kill the overgrowth of too much bacteria in the small intestine.
You will want to use specific herbs to kill the type of SIBO present, depending on whether you have hydrogen-dominant SIBO, methane, or hydrogen sulfide.
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Someone who has both methane and hydrogen-dominant small intestinal bacterial overgrowth will want to use herbs for both methane and hydrogen-dominant SIBO.
For Example:
Berberine and neem are natural antimicrobials for hydrogen-dominant SIBO.
Allicin extract and essential oils of oregano, cinnamon, and thyme are herbal antimicrobials used for methane-dominant SIBO.
Oregano oil is effective for hydrogen sulfide SIBO.
In this study, herbal antimicrobials were shown to be as effective as antibiotics.
Benefits of herbal antimicrobials for SIBO
One of the benefits of using herbal antimicrobials for bacterial infections and SIBO instead of antibiotics is antimicrobials such as the oregano essential oil also kill candida.
Many people who suffer from SIBO also have small intestinal fungal infections. If candida is present alongside SIBO, herbal antimicrobials are best, as antibiotics do not kill candida.
The use of antibiotics can also provide candida with the opportunity to overgrow since antibiotics also kill many beneficial bacteria that would keep candida in balance. Antibiotic resistance is also increasingly common these days, so it can be beneficial to use herbal antibiotics and various natural antimicrobials to reduce small intestinal bacterial overgrowth.
Antimicrobials for SIBO are used during the “killing phase” of a SIBO protocol. Phase 2 of the SIBO diet is implemented alongside herbal antimicrobials for the best results.
During the killing phase, antimicrobials are used for 4-8 weeks. In some situations, antimicrobials may be used longer. However, antimicrobials are not meant to be used indefinitely as they are detrimental to the gut microbiome long term.
If SIBO symptoms persist after using antimicrobials, it is necessary to retest to see what results were achieved.
It is also crucial to ensure that you identified and addressed the underlying root cause of SIBO to prevent relapse. Sorry, healing SIBO isn’t as easy as just taking antimicrobials. The upper digestive system’s function must be addressed, among other things.
Grab my gut health guide where I teach how to support the primary organs involved in the upper digestive system and the symptoms associated with each digestive organ.
Handling die-off reactions from using antimicrobials such as oregano oil for SIBO
In some situations, a die-off reaction can occur as a result of taking antimicrobials such as oregano oil for SIBO. The antimicrobial properties of oregano oil kill bad bacteria and are used as a natural treatment for SIBO. But just because oregano oil is natural does not mean it is ineffective.
The active ingredients in oregano oil that contribute to its antibacterial properties are carvacrol and thymol. Oregano oil has been shown to have an antimicrobial effect on E. coli due to carvacrol puncturing the cell membrane of gut bacteria.
Unfortunately, Oregano oil can also kill good bacteria in the gut thus, it is important to use probiotic supplements for SIBO to reinoculate the digestive tract with beneficial bacteria that support the immune system.
A die-off reaction can be caused by a massive increase in fungal and bacterial toxins from dying bacteria. If a die-off reaction occurs, it is best to consult your practitioner and reduce or stop the use of antimicrobials for a few days. Candida frequently occurs alongside SIBO, and candida die-off symptoms can occur as a result of taking oregano oil, as it is effective at killing harmful bacteria and candida.
The liver is easily overwhelmed by endotoxins produced by dying bacteria. When a die-off reaction occurs, it is essential to ensure that the livers detoxification pathways are open.
Binders such as activated charcoal and bentonite clay can be used alongside antimicrobials to help prevent side effects while also binding and escorting toxins out of the body. Taking activated charcoal for SIBO is one of the best ways to help prevent SIBO die-off symptoms.
Antimicrobial supplements for SIBO
There are several types of effective antimicrobial products used for SIBO. It is best to choose an herbal antimicrobial or mixture containing herbs that are effective for the type of SIBO you have tested positive for.
Biotics Research ADP contains oil of oregano, which is effective for hydrogen-dominant SIBO, methane-dominant SIBO, and candida. Oregano oil is a natural and diverse antimicrobial for SIBO.
Metagenics Bactrex contains oregano oil and thyme, which is great for methane-dominant SIBO. Bactrex is effective for candida as well. Oregano oil was one of the herbal antimicrobials I used to eliminate my candida overgrowth.
Thyme, oregano, and lemon balm are herbal antimicrobials found in Metagenics Candibactin Ar.
Berberine is one of the best antimicrobials for hydrogen SIBO found in Metagenics Candibactin BR with additional herbs for liver support.
Thorne berberine is another supplement for hydrogen-dominant SIBO
For a comprehensive list of additional antimicrobial supplements for SIBO, refer to the SIBO doctor dispensary guide.
When taking antimicrobial supplements for SIBO, it is best to work with your practitioner to select the correct supplement, dosage, and duration.
If you are struggling with SIBO, Dr. Nirala Jacobi from the SIBO Doctor has a very informative patient SIBO success course to beat SIBO for good and resolve your digestive issues. This course covers
• additional underlying causes of SIBO
• testing for SIBO
• Symptoms of SIBO
• types of SIBO
• biphasic SIBO diet
• antimicrobials for SIBO
and much more!
Dr. Nirala Jacobi has been my go-to resource for information on SIBO. There is so much to know about SIBO, and the SIBO success plan covers all the essentials you need to know about SIBO to beat SIBO for good.

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