Fig. 5

Impact of geraniol-based intervention on the intestinal microbiota structure in IBS patients. a Principal component analysis of Euclidean distances between the genus-level intestinal microbial profiles of IBS patients at the baseline (orange), after four-week intervention (red), and at follow-up after a further four weeks (olive green). Ellipses include the 99% confidence area based on the standard error of the weighted average of sample coordinates. A trend towards decreasing PC2 values after the intervention was observed (Wilcoxon test, P = 0.14). b Box plots showing the distribution of the relative abundance values of IBS discriminant taxa over time (T1, baseline; T2, after four-week intervention; T3, at follow-up). Data are shown for the whole IBS cohort and for IBS subtypes. The increase in the relative abundance of Collinsella and Faecalibacterium at T2 compared to the baseline (T1) was statistically significant (*, Wilcoxon test, P = 0.04)