Plectranthus amboinicus (commonly known as Indian borage or Cuban oregano) has been used in traditional medicine for a variety of ailments, including respiratory issues and infections. In recent years, scientific studies have investigated its potential antifungal properties. In vitro research has demonstrated that extracts from P. amboinicus possess activity against several fungal species such as Candida albicans, Aspergillus niger, and Trichophyton rubrum. The antifungal effect is generally attributed to the presence of bioactive compounds, including thymol, carvacrol, and eugenol, which are known for their antimicrobial properties.

However, while laboratory studies show promising results, clinical evidence in humans is lacking. Most of the available research is limited to test tube and animal studies, with very few, if any, well-conducted human clinical trials confirming its efficacy or safety for treating fungal infections. Therefore, while there is some scientific basis for its antifungal potential, the evidence is preliminary and not robust enough to strongly recommend its use for this purpose in clinical practice. Traditional use may also play a role, but the scientific evidence currently available warrants only a modest rating.