The old herbal and eclectic books contain a wealth of information. Since the equine was an important economic animal for transportation and draft, horse doctors used all the tools of the day to keep them healthy and working. The understanding of diseases certainly was not as advanced as today. These old texts can supply practical information on herbs that is as valid today as it was in the previous centuries. The study of these antiquarian books can lead to understanding why some treatments, such as parasite control, may not work well today. Other useful herbs, such as gentian, have been forgotten and their use should be revived.