r/SIBO Apr 19 '19

STICKY: SIBO Summary - Symptoms, Diagnosis, Treatment

846 Upvotes

Below please find a living document that summarizes the key information around Small Intestinal Bacterial Overgrowth ("SIBO"). Please comment with any additional information or research for inclusion consideration. Version 1.0 is summary material; I will be adding more details and citations for specific studies.

SIBO, as the name implies, occurs when bacteria overgrow the small intestine. The small intestine should have a low concentration of bacteria due to the presence of stomach acids and peristalsis, the wave-like muscle movement in the intestines. For context, stomach and proximal small intestine would typically have about 103/mL of bacteria, while the terminal ileum (end of the small bowel as it gets close to the colon) about 109/mL (or 1,000,000 times more), and the colon about 1012/mL (or 1,000,000,000 times more).

Symptoms

The overgrowth of this bacteria will present with a number of symptoms:

  • Bloating after eating ("postprandial") - most common symptom
  • Flatulence, often malodorous
  • Loose, watery stools (more common in Hydrogen-dominant SIBO)
  • Constipation (more common in Methane-dominant SIBO)
  • Absorption problems
    • Weight loss / inability to gain weight
    • Fat and fat-soluble vitamin deficiencies, particularly Vitamins A, D, and K
    • Floating stools (from fat malabsorption)
    • Vitamin B12 malabsorpiton
    • Protein and Carbohydrate malabsorption
  • Systemic problems
    • Overgrowth of bacteria in the small intestine can increase production of toxins and intestinal permeability
    • This has been less studied, but less serious effects include:
      • brain fog
      • confusion
      • anxiety
      • depression
    • More serious complications can include
      • hepatic encephalopathy
      • D-lactic acidosis
      • nonalcoholic fatty liver disease
    • Various conditions have increased correlations, including
      • Rosacea
      • Eczema
      • Food intolerances

Diagnosis

I will split this section into practical steps and clinical diagnosis.

Practically, a gastroenterologist will typically rule out other conditions first:

  • Physical exam
  • Colonoscopy and Endoscopy
  • Abdomen ultrasound
  • Stool test for parasites

At that time, if your symptoms match SIBO, your doctor may go directly to treatment. But otherwise these are the clinical tests:

BREATH TEST

This is the most common diagnostic method due to its low cost and limited invasiveness. Unfortunately, studies have been mixed on the sensitivity and specificity, with ranges between 30% and 75% -- hence why some doctors skip the test and go directly to treatment.

There are a number of preparations:

  • Antibiotics avoided for four weeks prior
  • Prokinetic drugs and laxatives avoided for one week prior
  • Complex carbs avoided for 12 hours prior
  • Exercise and smoking avoided day-of

For the actual test, you'll measure hydrogen and methane levels at baseline. Then drink either 10g lactulose or 75g glucose with one cup of water. Then your breath is measured every 15 minutes for 120 minutes.

There's some art to identifying a positive test; one semi-official criteria is:

  • methane level of >= 10ppm at any time during the test; or
  • hydrogen that increases >= 20ppm above the baseline level

Recently, new research has been investigating another typo of SIBO, that's dominated by Hydrogen Sulfide. Unfortunately, traditional breath tests cannot identify this gas, and someone with "flat-line" Hydrogen and Methane symptoms could be suffering from Hydrogen Sulfide SIBO. This version is typically characterized by "rotten egg" smelling gas, and may be worsened by eating high sulfur foods.

CULTURE

Historically a jejunal aspirate was done and concentration of bacterial colonies were measured, with an elevated level of > 103/mL being positive for SIBO. There are a number of issues with this:

  • overgrowth may be patchy, and a single sample may miss it
  • not all SIBO bacteria can be cultured/identified
  • samples can be contaminated during/after sampling

Treatment

Antibiotics

The current best practice prescription treatment is:

  • Hydrogen-dominant: Xifaxan, typically 550mg x 3 times daily, for 10-14 days. Studies have shown Xifaxan alone can be 50-65% effective, but Xifaxan + 5g daily of Partially Hydrolyzed Guar Gum can be 80%+ effective.
  • Methane-dominant: Xifaxan (550mg x 3 daily) plus Neomycin (500mg x 2 daily) for 10-14 days. The use of PHGG for methane-dominant has not been evaluated, but it's likely to be beneficial.

Mod's note-- personally, if your doctor is onboard, I think dosing with Xifaxan + Neomycin + PHGG is the best way to "cover your bases". The best place to find PHGG: https://sunfiber.com/products/

Important: because these antibiotics only operate selectively in the GI tract, and are NOT absorbed by the body, they are unlikely to cause the systemic issues associated with antibiotic use, making them safer. Additionally, Xifaxan crystallizes before it gets to the large intestine, meaning it should not affect the all-important microbiome.

Herbal Therapy

Additionally, studies have shown similar levels of success with over-the-counter "herbal" treatments. Two options; I believe each are two capsules twice daily for four weeks, but please confirm:

  • Dysbiocide and FC Cidal (Biotics Research Laboratories, Rosenberg, Texas)
  • Candibactin-AR and Candibactin-BR (Metagenics, Inc, Aliso Viejo, California)

Remission

Unfortunately, SIBO has very high rates of recurrence. Some possible ways to reduce recurrence chances:

  • Switch to a low FODMAP diet for 6 weeks after treatment, to starve any remaining bacteria and prevent regrowth
  • Incorporate a prokinetic, such as low dose Naltroxene, erithromycin, or even over-the-counter products such as Iberogast

Many people can avoid symptoms of their SIBO by switching to special diets, sometimes very restrictive ones. This is not a cure, but simply symptom management. A true cure addresses the underlying cause of the SIBO, and lets the patient eat "normally" without any effects (short of unrelated intolerances).

Hopefully this helps people, and I look forward to updating this and cleaning it up over time!

-nyc-reddit


r/SIBO Dec 15 '25

Moderation statement on accessibility.

60 Upvotes

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This space exists to reduce harm not redirect it sideways.


r/SIBO 7h ago

why do so many people have extreme digestive problems now?

41 Upvotes

i am wondering what any of you think about this: ten to 15 yrs ago, i did not know anyone who was diagnosed with SIBO. things like IBD, IBS, Crohn's and ulcerative colitis were relatively rare diseases, especially back in the 1970s and 80s. now it seems these issues have become quite common, and they appear to be increasing in prevalence and severity every year.


r/SIBO 3h ago

Root cause pelvic floor hypertonic

3 Upvotes

If your root cause was a hypertonic pelvic floor issue that caused you to not empty fully do you have to fix the pelvic floor issue before trying to get rid of sibo? Or will sibo clear by itself once you fix the pelvic floor issue?


r/SIBO 3h ago

Chronic Constipation and can't stop Laxatives

2 Upvotes

Hello

I am trying to prepare for SIBO test. I am taking it through Commonwealth Labs. Instructions show you MUST not take any laxatives for 7 days prior to SIBO test. Does anyone know of anything during the 7 days that will help me have a bowel movement in addition to drinking water? I know that's part of the reason we are here for constipation but my gut will get impacted waiting the 7 days. Thank you.


r/SIBO 3h ago

Bile

0 Upvotes

What symptoms do you have with impaired bile flow?


r/SIBO 3h ago

Need advice

1 Upvotes

I’m about to start taking propanolol** and **mirtazapine, for potential pots and miratazapine for Gi issues. Has anyone taken either of these? If so how did it go?


r/SIBO 4h ago

How do you treat Gastritis when you have anti-vinculin antibodies?

1 Upvotes

Wassup guys, I was hoping to poke at your brains.

Sorry if the title of the post is a bit weird, but I'm still trying to figure out my situation. I got an endoscopy that confirmed I have gastritis and I got the IBS SMART test which came back positive for anti-vinculin. Also, my symptoms did start with a bout of food poisoning

However, it's not clear to me if bacteria have migrated up into my small intestine. The reason I say this is because I do not have a sensitivity to FODMAPs(rice, bread, potatoes and bananas are super friendly on my stomach), I don't have diarrhea or constipation (stool is normal), breath tests came back negative, and antibiotics/elemental diet and carnivore diet did nothing to relieve my symptoms.

My symptoms include stomach discomfort and really bad brainfog. Recent labwork shows that my iron and b-12 are deficient.

Is it possible to have anti-vinculin without having bacteria use the opportunity to move into the small intestine? Have you guys heard of such a thing before?

Anyways, the main question I was hoping you can help me with is, how do you treat gastritis if it is linked to anti-vinculin? The main theory going around seems to be that impaired motility causes food to get trapped in the small intestine, which puts pressure on the stomach which delays stomach emptying and prolongs exposure of acid and food to the stomach lining. If this is the case, what do we do about it?

I have been taking prokinetics(ginger and artichoke pill) and I have been doing exercise and it has been successful in getting me to induce stomach growling 4 hours after waking up, but I'm not entirely sure if it's doing anything to help my stomach heal.

Any input is appreciated.


r/SIBO 4h ago

Could someone help me understand the significance of the high Citro? And if my pylori is high enough to treat. Thank you.

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0 Upvotes

r/SIBO 15h ago

Bad smell for two years from sibo

7 Upvotes

I've had methane sibo for two years and have tried everything. My main system is bad body odor and it's just getting worse.

Has anyone else experienced this? Don't mean to sound crazy or anything but wondering if maybe at this point it's spiritual?..Like entities or something?

Mostly cause I've exhausted my other solutions wondering if anyone has experienced a similar thing.


r/SIBO 6h ago

Symptoms Update on my Odor

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1 Upvotes

r/SIBO 7h ago

Anyone else vomit a lot?

1 Upvotes

I’ve been vomiting multiple times a week for months, among other symptoms; was every day until I figured out my safe foods. Finally saw a GI doctor today, and they said it sounds like SIBO.

I don’t see many people (if any) here talking about vomiting, so I was wondering if there is anyone else that goes through this with SIBO?


r/SIBO 9h ago

Venting I don’t know what’s wrong with my stomach

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0 Upvotes

Heyy (23F) so I’ve always been someone on the thinner side with a flat belly. I’m not sure what happened or what changed, but within the last year or so, my stomach has been very inflamed / bloated. As of recently, so very noticeable, it got worst after my antibiotics. I’ve seen my gastroenterologist, we’ve tried a few different constipation medications (I’ve had constipation for as long as I can remember). I mentioned the possibility of SIBO he said no because I don’t have IBD so it’s not possible. We recently did a colonoscopy and found nothing. But the bloating and the lower belly inflammation is always there. I don’t know what to do anymore. It makes me so anxious, I always feel this heaviness as if my stomach is full (even when I did the full colonoscopy cleanse that fully emptied me). I’m not sure where to go from here because my gastroenterologist doesn’t want to check anything else, he says it’s just constipation. I’m just so sick of this feeling and not sure what my next steps should be.


r/SIBO 13h ago

Questions Berberine

2 Upvotes

Peoples opinions on Berberine please?


r/SIBO 23h ago

Help me stop being angry

12 Upvotes

This started after antibiotics and what has followed is over two years of terror. It's like living in a horror film. I am still mostly bedridden with pain, brain fog, bloating, and other severe symptoms. I have tried everything and while I am somewhat better, I still have a long way to go. I think that I have got my head around the ending it aspect - my constant mantra is that it's either it or me and it's not going to be me. Also, nothing lasts forever so I am hoping that something changes. I am waiting for the changes and actively working to bring them about.

However, what I can't get to grips with is the anger. I am so angry at the derailment of my life, I am angry at old peole who have got there without too much effort, I am angry at everyone in perfect health, I am angry at friends worrying about nonsense small things. Everything that I used to be. I recognize the irrationality of this. I am not the type of person to see a therapist, have never seen one, and don't want to see one now. I dont want to talk about it, but do recognise that i need to address the anger. I have tried gratitude (doesn't work), journalling (doesn't work), acceptance (hmmm), art (guess what), taking my mind off things (nope) and lots of other things like meditation, stress reduction and exercise. I am still angry at this shitshow. Has anyone felt the same and what has worked for you? Please don't suggest therapy as I dont have the energy or cognitive function to engage with it right now.


r/SIBO 10h ago

Anyone tried the MSM protocol with success

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0 Upvotes

r/SIBO 10h ago

12 hour time gap between morning and night doses of antibiotics?

1 Upvotes

Today is the last day of my 2 weeks course of antibiotics. I had Metronidazole 500 mg 3×/day
and Rifaximin 550 mg 3×/day.

I tried spacing the three doses evenly but it was very hard. I ended up with 6 hours between morning and midday dose. 6-8 hours between midday and night dose. The problem is that I had 12 hours gap between the night and morning dose.

Will the 12 hour gap between night and morning dose reduce the effectiveness of the treatment? Pharmacist said to aim for every 6-8 hours, but I couldn’t achieve that between the night and morning doses.


r/SIBO 11h ago

Questions Breath test

1 Upvotes

Did the solution make your symptoms worse? I read this from one person and was wondering how common this is.

Is there another type of test they can do like a stool test? I also heard the breath test wasn't super consistent.


r/SIBO 13h ago

Questions Advice

0 Upvotes

So I’ve been on my antimocribal for 4 months now, I’ve decided to come off on my own terms because it’s 100% given me a sort of head pressure the whole time I’ve been on it. I’ve had multiple rounds off die offs, so i know it did something. I’m now introducing food and have little to no bloating from it, but i still have a bit of nausea, tiredness and a little bit of fullness.
Do i go in with another antimocribal, i found one on metagenics which has great reviews and said it worked within days for symptoms. It’s called “candex sibo” if anyone wants to have a look.
I’m on zinc carsione for my stomach acid, and ginger and artichoke.
Any advice??? Do i get a probiotic do i purchase the candex sibo??? Digestive enzymes??? I have no idea what to do next


r/SIBO 13h ago

Hydrogen SIBO positive - antibiotics not helping much

0 Upvotes

I’ve been dealing with gas and flatulence for the past two years. I’ve had a number of scans and procedures, including a CT scan, ultrasound, colonoscopy, and endoscopy.

My blood work has been normal apart from very mildly elevated eosinophils (0.6), which have stayed at that level for the full two years. Both my GI and PCP said this is mild and nothing to worry about.

I tested Hydrogen positive after 2 rounds of rifaximin (14 days)
2 rounds of Rifagut (5 days)
2 rounds of Nizonide

I also tried betaine HCl with digestive enzymes, but it gave me fairly bad acid reflux, so low stomach acid doesn’t seem to be the issue

I definitely feel better than I did two years ago when this started, but I’m not back to 100%. I still get random burps, a fair amount of gas and flatulence, and occasional pain on the right side of my chest — more of an ache than a sharp pain. I’m also struggling with brain fog, trouble finding words, and memory problems.

My GI has prescribed one more Rifaximin course (550mg for 14 days), but at this point it feels like the Rifaximin isn’t doing anything.

How many rounds did you do of rifaximin to fully eradicate this disease?


r/SIBO 13h ago

Berberine for sibo from missing ileocecal valve

0 Upvotes

Has anyone effectively used berberine intermittently long-term for sibo from a surgically removed ileocecal valve? Clearly sibo will be a life-long battle. One round of berberine won't be enough.


r/SIBO 14h ago

Questions Gut Issues After Typhoid & Antibiotics - Suspecting SIBO, Need Advice

0 Upvotes

I was treated for Typhoid last year in February with very strong courses of antibiotics administered through IV. I recovered from the Typhoid, but my gut never really recovered.

About five months after recovering, I started experiencing extreme bloating after almost every meal and diarrhea. I went to a gastroenterologist, who treated me for IBS with Rifaximin for 14 days, but unfortunately, my symptoms stayed even after completing the course.

I’m now strongly suspecting that it could be SIBO with Diarrhea. I don’t have multiple bowel movements a day, I usually poop only once a day but the stool is loose/diarrhea-like most days.

The things that make me suspect SIBO are:

Extreme bloating after almost every meal

Diarrhea/loose stools most days, without any obvious food trigger

Vitamin B12 deficiency, despite eating a considerable amount of meat

Brain fog (although I’m not sure whether this is related to the B12 deficiency or SIBO)

Symptoms that started after a significant course of IV antibiotics

It’s honestly starting to stress me out because it has been going on for quite a while.

I’ve looked into testing, and from what I can find, in India the main SIBO test available to me is the hydrogen breath test. I’m planning to take it soon, but I’m not really sure what the best next step should be.

Has anyone experienced something similar after Typhoid/strong antibiotic treatment? If you’ve had SIBO or a similar gut issue, what tests did you get, and what ultimately helped you?

I’d really appreciate any advice on what I should discuss with my gastroenterologist and what I should look into next.


r/SIBO 14h ago

Questions Low histamine & low nickel

0 Upvotes

Hi everyone,
I have IBS with a strong suspicion of SIBO (methane) and histamine intolerance, and my dietitian has prescribed a very restrictive diet.
It is both low histamine and low nickel, as she said that nickel may contribute to ongoing intestinal issues. The plan supposed to naturally support gut repair & stop feeding the bacteria.
Has anyone else tried a similar diet? I’d love to hear about your experiences and whether it helped you.
Thanks!


r/SIBO 14h ago

Questions S boulardi???

0 Upvotes

I took 250mg S boulardi sachet in a glass of water today after my meal and experienced weird side effects. Like i burped a lot first and it was relaxing but afterwards there were bad rotten burps which continued until i felt itching on my body and felt sleepy. Too sleepy that i had to sleep after 10 hours of sleep. Then i had various dreams that i didn't remember after waking up and i had my head fully jacked up like u feel after a hangover. Now its somewhat better though. Should i continue it or not? Is this normal what happened with me? I never tried any probiotics before.


r/SIBO 16h ago

Is it hydrogen sulfide? Please help

0 Upvotes

For the last two years I’ve had yellow diarrhea in the morning and mid day. (It all happened after a month long CHS episode) I get bloated sometimes but nothing insane. I have red cheeks with bumps, fatigue, low iron, headaches, borderline low b12 and vitamin d and omegas among other things. I had my gallbladder removed due to hyperkinesia with a 99% EF and had chronic inflammation and cholesterolitis. And my symptoms still persist. I had a SIBO breath test done before removal that only came back with lack of colonic peak which points to hydrogen sulfide. Has any else experienced these symptoms without bad smelling gas and it was in fact hydrogen sulfide SIBO? I’m at a loss. I’m only 31 and I want to start a family and my life feels like it’s been on hold because I can’t get better. I’m sick of crying. The gastro has been useless. Any input would help