Objectives: The aim of the study is to investigate the effect of a preparation containing St. John's wort on promoting skin recovery in a human model of mechanical skin irritation compared to placebo. Material and methods: This study, which lasted eleven days, involved 10 participants without skin diseases and skin damage at the test sites located on the forearm. On the participants' test sites using tape-stripping was induced mechanical skin irritation on the first day of the study. After that, participants treated one forearm with the preparation containing St. John's wort and the other one with placebo. The skin parameters that were used to monitor the recovery of the skin barrier were TEWL, skin hydration, erythema, and melanin. GraphPad Prism 6 (GraphPad Software inc., La Jolla, California, USA) was used for statistical analysis, and data were analyzed using a two-way analysis of variance (Two-way ANOVA) for repeated measurements and Sidak post-hoc test. Results: A statistically significant difference was found between the values of TEWL at the sites where preparation containing St. John's wort were applied compared to placebo (p = 0.0396). Post-hoc analysis found a statistically significant difference on the first day after application of St. John's wort. No statistically significant difference was found between the values of skin hydration, erythema and melanin at the sites where the St. John's wort preparations were administered compared to placebo. Conclusion: The administration of the tested preparations lowered the TEWL values, suggesting a faster recovery of the skin barrier after mechanical irritation, while the measurement of the skin hydration, erythema and melanin values did not indicate that there was a faster recovery of the skin barrier at the test sites where the St. John's wort preparation was applied compared to the sites where placebo was applied which is why more research with more participants is needed.