The aim of this study was to evaluate the effects of adding various medicinal plants to kombucha medium and to analyze the changes that occur to its physicochemical, antimicrobial, and sensorial properties. In the first part, measurements were made to determine IC₅₀ value, total phenolic content, total flavonoid content, minimum inhibitory concentration, pH, organic acids, and sensorial properties of kombucha that contained cinnamon, cardamom, or Shirazi thyme. Results showed that kombucha samples containing cinnamon exhibited higher antioxidant and antimicrobial activities, more organic acids, and better sensorial scores. In the second part, properties of kombucha containing 25%–100% concentrations of cinnamon were evaluated. The result showed that by increasing the cinnamon concentration, certain increases were observed in the amounts of organic acids and in the magnitudes of antioxidants and antimicrobial activities. In conclusion, antioxidant and antimicrobial activities of kombucha can be increased by adding medicinal plants, especially at higher concentrations.