Oregano oil is dominated by carvacrol, a phenol with formidable antifungal and antibacterial activity. In laboratory terms it is one of the strongest botanical antimicrobials known, and against a stubborn toenail fungus it is often what people turn to when tea tree has not been enough.
That strength is not free. Phenols are aggressive toward skin. Oregano oil applied at anything like full strength will redden and burn, and it deserves more caution than anything else in this index apart from raw garlic.
Use it deliberately, at proper dilution, on the specific spot that needs it — not as a general foot treatment.
