SIBO and Rosacea: What the Studies Show About Skin and Gut

In short: several studies have found SIBO more often in people with rosacea than in people without it. A 2025 meta-analysis of 6 studies put the rate at about 36% in rosacea compared with 9% in controls². In one 2008 trial, clearing SIBO with the antibiotic rifaximinRifaximin An antibiotic that is barely absorbed into the bloodstream, so it acts mainly inside the gut. It is a common prescription treatment for SIBO. cleared or greatly improved the skin in most patients, although the doctors rating the skin knew who had been treated¹. The evidence is not consistent, though: a 2015 study found no more SIBO in rosacea than in controls³, and no large, fully blinded trial has tested SIBO treatment for rosacea.

Rosacea is a long-term skin condition that causes facial redness, visible blood vessels and sometimes pimple-like bumps. This guide covers what the research on SIBO and rosacea shows, how strong it is, and what is known about other skin conditions.

How common is SIBO in rosacea?

Part of the disagreement may come from the tests used: the 2008 study used both lactuloseLactulose A synthetic sugar the body cannot digest or absorb. As a breath-test substrate it travels the whole small intestine, which also makes false positives more likely. and glucose breath tests, while the 2015 study used only the glucose test¹³. The two tests do not always agree; see breath tests explained. The 2024 study’s authors also note that it is unclear whether SIBO contributes to rosacea or whether both are results of a shared problem with the immune system⁴.

Does treating SIBO help rosacea?

The best-known study is the 2008 trial from Genoa¹:

• People with rosacea and a positive breath test were randomized to rifaximin (1,200 mg a day for 10 days) or a placebo.
• In the 28 whose SIBO was cleared by rifaximin, the skin cleared in 20 and greatly improved in 6 more. Of the 20 on placebo, 18 stayed the same and 2 got worse.
• When the placebo group was switched to rifaximin, SIBO cleared in 17 of 20, and 15 had complete resolution of rosacea.
• In people with a negative breath test, rifaximin did not help: 13 of 16 stayed the same.
• The improvement lasted at least 9 months.

These results are striking, but the trial has an important limit: the two dermatologists who rated the skin knew which treatment each patient had received¹. The 2025 meta-analysis pooled the treatment results and found that rifaximin improved or cleared rosacea in 57.9% of patients, and in up to 85.7% of those whose SIBO was cleared². That meta-analysis is published in Russian, so we could assess only its English abstract, and it included only 6 studies.

In the 2015 study, where SIBO was no more common in rosacea, 6 of the 7 people whose SIBO was cleared had a marked improvement in their skin, but the numbers were too small to draw conclusions³. The same study found that Helicobacter pylori infection was much more common in rosacea (49% vs. 27%), and that clearing it led to improvement in 35 of 36 people³. See our guide to H. pylori and SIBO.

Herbal treatment

A 2024 open-label study gave 16 adults with SIBO a combination of herbal supplements for 10 weeks. Participants were chosen because they had SIBO, not rosacea, and the researchers measured facial redness with photographs. Facial redness fell by 20% at week 10, though it had not changed at week 6 and did not change further in those who continued to week 14⁵. The study had no control group and 4 people dropped out. The supplements were provided by their manufacturer, and the senior author has consulted for skincare and pharmaceutical companies⁵. Treat it as a pilot result. For what is known about herbal SIBO treatments in general, see herbal antimicrobials.

Should people with rosacea be tested for SIBO?

We found no guideline that recommends routine SIBO testing for rosacea. Testing makes most sense if you also have digestive symptoms such as bloating, abdominal pain or a change in bowel habits; see SIBO symptoms and our diagnosis guide. Rifaximin did not help rosacea in people without SIBO in the 2008 trial¹, so treating SIBO “just in case” is not supported. Standard rosacea treatment from a dermatologist remains the first step.

Other skin conditions

• Chronic hives (urticaria). In a 2013 study of 48 people with chronic spontaneous urticaria, 13 had SIBO. Treating it did not improve their hives, while treating H. pylori in 11 people did⁶.
• Acne, eczema and psoriasis. We found only letters, case reports and reviews on SIBO and these conditions, and no controlled studies.

Common questions

Can SIBO cause rosacea?

It has not been proven. SIBO is more common in rosacea in most studies², and treating it helped in one trial with unblinded assessors¹, but that does not show that SIBO causes rosacea.

What antibiotic was used for SIBO in rosacea?

Rifaximin, 1,200 mg a day for 10 days, in the 2008 trial¹. It is the most studied antibiotic for SIBO; see our antibiotics guide.

Does rosacea come back after SIBO treatment?

In the 2008 trial, the improvement lasted at least 9 months¹. SIBO itself often returns, so addressing its cause matters; see preventing SIBO relapse.