<p>In this scientific article, the processes of heat transfer and airflow in solar dryers were simulated using the Computational Fluid Dynamics <br /> (CFD) method, and the possibilities of effective and high-quality drying of the medicinal plant — Plantago major (common plantain) — were investigated. The main purpose of the study was to optimize the solar dryer design, increase the drying rate, and preserve product quality through the use of CFD technologies. Using the ANSYS Fluent software, the internal temperature distribution, airflow velocity, and temperature gradients within the drying chamber were modeled. According to the simulation conditions, the air heated by solar energy was maintained within the temperature range of 55–65 °C and directed onto the product being dried. The initial moisture content of the plantain leaves was 82%, and after 3.5–4.5 hours of drying, it decreased to 10–12%. The CFD simulation results demonstrated the following advantages: the airflow was uniformly distributed within the dryer, ensuring equal thermal exposure to all leaves; efficient use of thermal energy led to a reduced drying time; the retention of biologically active compounds (flavonoids, vitamins) in the dried product was ensured; based on CFD analysis, recommendations were developed for improving the internal geometry of the dryer and the design of the air inlet and outlet channels. The simulation results were compared with experimental observations, and a high degree of agreement was recorded. The <br /> CFD-based model significantly improved the dryer’s efficiency, enhanced drying quality, and minimized heat losses. This study demonstrates the high potential of CFD-based approaches for the scientific design and practical implementation of solar dryers intended for drying medicinal plants.</p>