Acute respiratory tract infections in children are the most common reason for primary care appointments. Although the vast majority of cases are viral, antibiotic therapy, which involves more risks than benefits in these patients, is still overused, contributing to antibiotic resistance and adverse effects. Almost all recommendations indicate avoiding such approach and use symptomatic treatment supplemented with plant-based formulations instead. There is abundance of different medicinal plants that contain compounds with proven antiviral, antioxidant and immunomodulatory properties, which effectively support the combat against respiratory infections, especially if combined in one product (synergism). Contemporary rational phytotherapy assumes a scientific approach to plant-derived formulations, and it should be emphasised that the registration of herbal medicines is subject to the same restrictions as in the case of synthetic drugs. The paper discusses the composition and activity of compounds contained in medicinal plants and their role in the treatment of respiratory tract infections, with main focus on Pelargonium sidoides and elderberry, the properties of which have so far been the most thoroughly investigated and described. Their efficacy and safety in different forms of respiratory tract infections were discussed, showing that the use of products based on these plants significantly reduces disease duration and severity of clinical symptoms, as well as the need to use other agents, including antibiotics. The reasons for the use of Pelargonium sidoides preparations in the prevention and treatment of COVID-19 were also presented.