The COVID-19 pandemic has renewed global interest in medicinal plants as accessible sources of prophylactic and supportive therapies. Ethnobotanical research provides an important foundation for developing plant-based medicines with preventive and therapeutic potential. This study aimed (1) to investigate the distribution and indications for the use of medicinal plants in the prevention and relief of COVID-19-related symptoms among the Bulgarian population, and (2) to identify culturally significant species with potential for further development as antiviral agents. A total of 513 respondents from different regions and demographic groups in Bulgaria were interviewed. Their knowledge regarding the use of medicinal plants for COVID-19 prevention or treatment was quantitatively assessed using ethnobotanical indices: relative frequency of citation (RFC), informant consensus factor (FIC), fidelity level (FL), and use value (UV). Participants reported 45 species belonging to 43 genera and 23 families. The highest RFC and UVs were recorded for Matricaria chamomilla L., Tilia sp., Thymus vulgaris L., Zingiber officinale Roscoe, Mentha sp., Citrus x limon (L.) Osbeck, Rosa canina L., and Sideritis scardica Griseb. Culturally significant species identified were Thymus vulgaris L., Matricaria chamomilla L., Tilia sp., Mentha sp., Sideritis scardica Griseb, Zingiber officinale Roscoe, and Citrus x limon (L.) Osbeck. This ethnobotanical survey in Bulgaria documents culturally important medicinal plants that may have potential applications in prophylaxis and complementary therapy for COVID-19.

Еthnobotanical research provides an important foundation for developing plant-based medicines with preventive and therapeutic potential. This study aimed (1) to investigate the distribution and indications for the use of medicinal plants in the prevention and relief of COVID-19–related symptoms among the Bulgarian population, and (2) to identify culturally significant species with potential for further development as antiviral agents. A total of 513 respondents from different regions and demographic groups in Bulgaria were interviewed. Their knowledge regarding the use of medicinal plants for COVID-19 prevention or treatment was quantitatively assessed using ethnobotanical indices: relative frequency of citation (RFC), informant consensus factor (FIC), fidelity level (FL), and use value (UV). Participants reported 45 species belonging to 43 genera and 23 families. The highest RFC and UV values were recorded for Matricaria chamomilla L., Tilia sp. L., Thymus vulgaris L., Zingiber officinal Roscoe, Mentha sp. L., Citrus × limon Osbeck, Rosa canina L., and Sideritis scardica Griseb. Culturally significant species identified were Thymus vulgaris L., Matricaria chamomilla L., Tilia sp. L., Mentha sp. L., Sideritis scardica Griseb, Zingiber officinale Roscoe, and Citrus × limon Osbeck. This is the first ethnobotanical survey in Bulgaria documenting culturally important medicinal plants with potential applications in prophylaxis and complementary therapy for COVID-19.

During the COVID-19 pandemic, herbal medicine use - encompassing medicinal plants and phytoproducts - was widely reported globally, yet the therapeutic str