Rosacea

A striking clinical trial, not just an association

Rosacea, a chronic condition causing facial redness, papules, and pustules, has been linked to small intestinal bacterial overgrowth, or SIBO, in several studies. A landmark study found SIBO in 52 of 113 rosacea patients, compared with just 3 of 60 healthy controls, a striking difference. Patients with confirmed SIBO were then randomised to receive rifaximin, an antibiotic that targets gut bacteria, or placebo. Among those treated, rosacea completely cleared in 20 of 28 patients and greatly improved in 6 more, while the placebo group stayed the same or got worse. This improvement was still holding at 9 months of follow-up.

Source: Small Intestinal Bacterial Overgrowth in Rosacea: Clinical Effectiveness of Its Eradication

A specific gut bacteria signature

Beyond SIBO specifically, people with rosacea tend to show a distinct gut bacterial pattern, with reduced levels of Lactobacillus, Prevotella copri, and Faecalibacterium, and increased levels of other bacteria including Bacteroides and Ruminococcus. Researchers believe this imbalance may trigger the immune and inflammatory pathways involved in rosacea flares, though the exact mechanism isn't fully settled.

Source: An Overview of Small Intestinal Bacterial Overgrowth and Gut Microbiota in Patients with Rosacea

The evidence isn't fully consistent

Not every study agrees. A separate cohort study found no statistically significant link between SIBO and rosacea, and current clinical guidance stops short of recommending routine SIBO breath testing for everyone with rosacea, given how inconsistent the diagnostic tests can be. This is a case where a striking clinical trial exists alongside genuine uncertainty at the population level, so it's worth treating as a promising, specific finding rather than settled for every rosacea patient.

What this means for you

Rosacea needs proper dermatological diagnosis and treatment, since topical and oral treatments remain the well-established first-line approach. For rosacea that hasn't responded well to standard treatment, particularly alongside digestive symptoms like bloating or irregular bowel habits, it's reasonable to ask a doctor about testing for SIBO given the strength of the trial evidence above. A varied, plant-rich diet supports the same gut bacterial balance this research ties to calmer rosacea. That's the same idea behind GutLab, everyday gut health starts with regularly feeding the microbiome a broad range of plant-rich ingredients.