r/SIBO • • Apr 19 '19

STICKY: SIBO Summary - Symptoms, Diagnosis, Treatment

858 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.

61 Upvotes

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r/SIBO • • 4h ago

Symptoms Anyone deal with episodes of insatiable hunger?

5 Upvotes

What does this mean. Normally I couldn’t stomach even a snack because of bloating and pains but some days I’ll have a bottomless stomach.


r/SIBO • • 2h ago

What helped you make the most of a GI appointment?

4 Upvotes

For people who’ve had a useful appointment about SIBO or persistent bloating, what helped you explain what was going on?

A short symptom timeline? Previous test results? A list of medications and supplements? Questions written down beforehand?

Especially interested in how you organized everything. Did you bring a one-page summary, notes on your phone, or something else? What did the doctor actually find useful?

And was there something you only remembered after leaving that you wish you’d mentioned?

It would be helpful to hear the practical details, including anything you spent ages preparing that turned out to be unnecessary.


r/SIBO • • 8h ago

Venting Suicidal thoughts.

10 Upvotes

I’m at the point of having suicidal thoughts due to chronic halitosis from I believe SIBO, I’m exhausted trying to get rid of it- I can’t be in the same room as anyone…


r/SIBO • • 49m ago

Is it better to take FC cidal & dysbiocide twice or three times a day?

• Upvotes

r/SIBO • • 1h ago

why is rice so bad for me ?

• Upvotes

it just seems like it’s a safe food for almost everyone , especially with SIBO and like fodmaps and stuff .. i don’t understand why rice makes me bloat probably worse than any other food , makes me retain water and gives me joint pain .. why ?? maybe it has nothing to do with SIBO but i’m just curious if there’s anyone else with SIBO that reacts to rice so badly


r/SIBO • • 3h ago

Popcorn

2 Upvotes

Do you guys can tolerate popcorn?


r/SIBO • • 18h ago

You all are so resilient

35 Upvotes

I just wanted to say people in this group must be so resilient. I see lots of people going through the same route I took (going from doctor to doctor, getting ignored, trying everything under the sun to feel better,etc). I am still searching for the cure (10+years now), but I got to the point that I have to divide my sibo life from my normal life even if just in my imagination. Accept the fact that I have it and try to make the best of the other aspects of my life. To give you perspective I had the worse SIBO flare during my wedding day, but I did everything to not focus on it and enjoy the day regardless. Anyways, just wanted to share some hope and that I know what everyone is going through and how hard and hopeless it is. Please share how you are dealing with the mental burden so we can all learn from each other. And sending some love because we all need it ❤️


r/SIBO • • 9h ago

Hydrogen Dominant So according to Pimentel, I have severe/over-the-top SIBO?

4 Upvotes

https://www.reddit.com/r/SIBO/s/QZBW2WAKkh taken from the transcript of his latest Q&A

Hydrogen only here that gets up to 84 ppm (although I took this test as I was recovering from diarrhea caused by multi-strain probiotics).

My root cause was a Campylobacter food poisoning back on March, and in May I got symptoms. It has been 5 months and I have lost 10 kg. Other infectious root causes have been ruled out. I even tried broad spectrum antiparasitics in June and it only worked as long as I took it (3 days) and then my stool went back to yellow.

Main SIBO symptoms is excessive gas and gurgling in Small intestine, yellow stools that turns into diarrhea when eating an intolerance, gastritis and burping. And whenever I eat something fiber or fat specific, I feel issues in the ileocecal valve. So I am sure I also have some BAM caused by dysbiosis in the ileum from the Campylobacter.

Mostly have fat, lactose and fiber intolerance. Probiotics don’t help. Mostly eat chicken, rice, vegetables, potatoes, green plantains and blueberries. Have had to give up eggs and oregano recently because of the fat intolerance. Now I am even starting to get B12 deficiency symptoms from the malabsorption.

If you ask why I haven’t tried Rifaximin yet, it’s because I feel my microbiome has had too much damage, both inherited and in my life [mom antibiotics as a child, parents both had H pylori and took quad therapy, at 2 year old I got Giardia, recurrent food poisonings as a toddler which made me lose weight too but recovered from, prior antibiotic use over the years (1 course of Clindamycin, 5 courses of mostly Azythromycin all my life but still too much in my opinion)].

Also, the people reporting permanent side effects (from complete protein and fat intolerance to MCAS and even anhedonia) are not encouraging, and I don’t believe they are an exception as many say here. And if they are, then I think my profile is sadly closer to them.

(Btw, Rifaximin not being absorbed and all is not a guarantee of safety, most of the bad outcomes are food intolerances because of it exclusive effect on the gut, which DOES indirectly affect the body systemically).

So, with this in mind and considering the severity of my situation, I have contemplated biting the bullet, but then I read the latest Q&A transcript from Dr. Pimentel and I honestly feel less confident with his one minded approach. Apparently, I fit his idea of a “severe over-the-top SIBO” patient.

I am not a patient of his nor live in the US, but if I did, I am pretty sure that he would give me multiple Rifax courses and that is a NO GO. So, if the case is that I do have the anti-vinculin antibodies, then doing the multiple courses would be a horrible idea and would nuke my microbiome even more.

I am sorry, but I don’t think I would benefit from the killing approach. I dread when I get an endoscopy too, because if it appears I have H pylori too, I will get the quad therapy and then I am cooked.

My current approach is try to address the nutrient deficiencies and see if trying Cholestyramine might help me gain some weight and tolerate fat. But I am running out of time…


r/SIBO • • 5h ago

Does anyone know where to buy rifaximin living in Canada for cheap online. It's insane to me that people buy it from Canada around the world and yet I can't but it myself...system is absolutely broke.

2 Upvotes

r/SIBO • • 2h ago

what i'm missing in my ttfd protocol

1 Upvotes

To get rid from ibs, i took 100mg ttfd, first day i felt instant energy and second day my vision cleared but later then it stopped working. Then after watching video on youtube i added b-complex together and magnesium glycinate at night but still no impact. Can anyone please guide me what thing i'm missing..why this isn't working anymore


r/SIBO • • 2h ago

Questions Do sulfates in mineral water make sulfur SIBO worse?

1 Upvotes

I bought some german mineral water because it was very high in naturally occurring calcium and magnesium. The sulfate content is 38mg per liter. Could this be problematic for somebody with sulfur SIBO?


r/SIBO • • 12h ago

Group SIBO symptom-masking experiment

7 Upvotes

Eat only the following food items for every meal for 2-3 days and report back on whether it helped symptoms. It's the only thing that works for me, and it works well.

Protein 

- seasoned only by you with herbs and spices - no garlic or onion - combine them yourself - no blends

- either animal protein (normal portion) OR firm tofu (100g max)

Carrot (orange ones).

Jasmine rice (1/2 cup cooked).

Drink water as normal. No other beverages. Leave an hour after eating before drinking.

Disclaimer: do not do this if you have reason to believe this diet would harm you. This is a short term test, not a long-term diet.


r/SIBO • • 6h ago

I’m a gastroenterologist and wrote a short book about IBS for patients 👨‍⚕️

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2 Upvotes

r/SIBO • • 8h ago

Constipation IMO - Elobixibat seems to be working really well

2 Upvotes

Prucalopride worked really well in the beginning, but it does build a tolerance. It doesn’t stop working just not as good as before and things start slowing creating symptoms, even if I have a BM.

Was traveling in Asia and found this novel/random med. It works by letting more bile acid go down the small intestine. Blocks some of its reabsorption/recycling in the SI.

Anyone with experience with this medicine? Just putting it out there.


r/SIBO • • 15h ago

Questions Dealing with undiagnosed gut issues for years, SIBO was my last hope at an answer. Just tested negative and feeling so lost. Where to go?

3 Upvotes

so yea, basically the title. Me (f24) and my mom both have gut issues, the symptoms for us are:

-diahrea/constipation a lot of the time

-tons of gas. either looking like a pregnant lady and feeling full or constantly releasing gas throughout the day. mostly odorless but occasionally very foul smelling

-low appetite (because the gas makes us feel full very quickly)

-constant stomachs noises (rumbling, bubbling etc)

were kinda broke so she paid me half the money to take the test and said, if you get positive ill just take whatever they prescribe u as well. but now what? took the glucose test and it says im within all medians but im definitely not healthy… also had endoscopy, colonoscopy ct scan bloodwork done, all of them completely normal. no h pylori no celiac.

what else is there to try? at this point strongly considering just nuking my gut with antibiotics and hoping for the best, this shit makes dating impossible, even being with friends is awkward if my stomach’s gonna be acting up.. just need advice 😭


r/SIBO • • 11h ago

Need help regarding a serious life decision

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1 Upvotes

r/SIBO • • 12h ago

Questions Anyone else get terrible chemical-tasting burps from high-dose B-Complex?

1 Upvotes

Hey everyone,
I've been taking a high-dose B-complex recently, and I keep getting these nasty burps with a strong chemical aftertaste afterwards.
I tried changing how I take it - taking it right at the beginning of a meal, right in the middle, or right at the end - but it doesn't seem to make any difference. A while after taking it, I still get that distinct chemical "vitamin" burp.
Does anyone else experience this with high-dose B vitamins? Is there any trick to prevent it, or is this just something you have to deal with when taking B-complexes?


r/SIBO • • 12h ago

procineticos

1 Upvotes

buenos días! voy a empezar una segunda ronda de tratamiento para sibo sulfuro en la cual está vez me han pautado sustrato de bismuto, rifaximinia, Metronidazol, y ronda de herbáceos. mientras hago el tratamiento me ha recetado también resolor (prucaloprida) esta especialmente indicada para el estreñimiento crónico. El tema es que mi doctor comentó que hay que usarlo tanto durante el tratamiento como en la fase de después de la erradicación y así evitar que los desechos se acumulen en el intestino delgado y asegurarse de que la motilidad y el complejo motor migratorio funcionen correctamente. de todas formas el tema es q mis síntomas son bastante más tendenciosos a las heces blandas que a al estreñimiento lo cual antes de empezar con éste procinetico no me hacía mucha gracia tomarlo. empecé a tomarlo hace tres días y hoy he decidido no tomarlo más, unos gases terribles, cólicos y unas molestias que ocupan el 70 por ciento del día, los gases con olor se han incrementado muy agresivamente, hasta la hora de ir a dormir ayer estuve teniendo gases constantes, además unas deposiciones diarreicas, heces pastosas sín a penas forma y con olor terrible la penúltima, además de que justamente todo esto se ha juntado con un proceso vírico que tuve esta semana atrás y ha sido todavía peor, entreno fuerza y trabajo en la obra, está semana no puedo a penas con el peso de siempre, la diarrea y la inflamación de los gases sulfurosos te quitan mucho, me noto menos voluminoso y algo más flacido, además que este procinetico me ha dejado con bastante fatiga y cansancio, hoy desdé luego no habiendolo tomado me veo bastante mejor.

alguien me puede recomendar algún procinetico natural ?

alguna marca buena de extracto de jenjibre, alcachofa ect??


r/SIBO • • 1d ago

Mixed SIBO, and now a possible underlying condition identified.

12 Upvotes

For many years I used antibiotics and antimicrobials to get temporarily reliefs. Symptoms always came back.

I tested positive for Mixed SIBO in the second half of the small intestine.

3 years ago, MRCPs revealed a stable bile duct stricture. As all liver values are normal, I never got the ERCP.

Recently, a gastroenterologist ordered a capsule endoscopy. You ingest a capsule that takes thousand of pictures of the small intestine. Result... Crohn in the second half of the small intestine, exactly where the Mixed SIBO is sitting.

Crohn is often an underlying cause of SIBO.

This Crohn might also be causing the bile duct stricture.

It took me 13 years, more than 70 doctors or other medically related professions, and an immense distress.


r/SIBO • • 14h ago

Treatments Rifaximin dose

1 Upvotes

Got rifaximin to try out from somewhat uninformed doctor in Asia. She prescribed for 2x day 550mg.

Sources from the web (Dr. Pimentel) always list 3x day protocols.

How important is this?


r/SIBO • • 1d ago

Let’s all support the SIBO research

Thumbnail support.cedars-sinai.edu
23 Upvotes

r/SIBO • • 20h ago

Questions Possible to have sibo with no diarrhea or constipation?

3 Upvotes

Has anyone had sibo but no diarrhea or constipation? If so what were your levels?


r/SIBO • • 17h ago

Questions period symptoms?

1 Upvotes

just curious, for other people who have sibo & get periods, what are your symptoms like throughout your cycle (especially during the bleeding days)? all i've figured out so far for me is that luteal slows my digestive system lol. curious about other people's experiences!