We have compared references to the use of medicinal plants for the treatment of respiratory tract diseases in horses in the literature of the 18th and 19th century with those in recent textbooks. Around a third of all plants covered in our research were already in use in the 18th and 19th centuries and are still listed as treatments for respiratory diseases in horses. About a quarter of all the plants are only mentioned in recent literature, either because their therapeutic potential was discovered only recently or because the plants are exotic and were formerly unknown in central Europe. In equine medicine, medicinal plants are largely used in combination with synthetic drugs and food supplements, possibly because of the limited approval of veterinary herbal remedies today. Before using phytotherapy for competition horses it is important to consider potential conflicts with anti-doping regulations. Such conflicts can also arise when certain herbs are fed unintentionally. There is scientific evidence for the effectiveness of only 25 % of the plants reviewed in the treatment of equine respiratory disease. Further scientific studies are required to assess whether veterinary medicinal registration is appropriate, which would lead to a broadening of the powerful application of herbs in equine medicine.