4. Oregano oil
Oregano oil contains thymol. According to a 2016 review, thymol has antifungal and antibacterial properties.
To treat toenail fungus, apply oregano oil to the affected nail twice daily with a cotton swab. Some people use oregano oil and tea tree oil together.
Both products are potent and may cause irritation or allergic reaction. Combining them may increase this risk.