**5. Conclusions**

An intrinsic and intriguing question that emerges from this study is to establish which topical application (hydrophobic EOs or hydrophilic Hys) is most suitable for healing different skin infections. Our short communication highlights an aspect still unexplored by the scientific literature regarding the real antimicrobial effectiveness of the active ingredients contained in Hys compared to the EOs from the same plant source. The use of odorous aqueous solutions with low concentrations of active ingredients in the treatment of minor and chronic skin infections is certainly interesting for the fight against antibiotic resistance. Furthermore, since the terpenic active ingredients are not very soluble in water, most Hys have a low number still present; *O. hirtum*, has only one. This makes these natural products also interesting for pharmaceutical companies who are looking for

new natural products with antimicrobial action, but need "standardizable" products to be tested in clinical trials conducted according to scientific rigor.

**Author Contributions:** Conceptualization, M.D.V., F.B.; Methodology, M.D.V., F.G., P.M.; Formal Analysis, M.D.V., A.S., F.G.; Investigation, M.D.V., A.S.; Resources, P.M., M.S.; Data Curation, M.D.V., L.B., M.R.P.; Writing—Original Draft Preparation, M.D.V.; Writing—Review & Editing, P.M., F.B., E.N., M.G.B., G.B. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** *M. didyma* and *M. fistulosa* plants were used in this study. Vouchers are deposited at the Herb garden of Casola valsenio (Ravenna, Italy) (Sauro Biffi).

**Acknowledgments:** Lori Morrison is gratefully acknowledged for manuscript proofreading.

**Conflicts of Interest:** The authors declare no conflict of interest.
