This paper pursues the lead of Bart K. Holland in utilizing classic literature as a guide to the pharmacologic potentialities of natural products. Instead of focusing on European texts, however, American medicinal plants are examined through the work of the influential naturalist Constantine S. Rafinesque (1783-1840). Rafinesque is discussed with special attention to his activities as a medical botanist. In particular, the plan species monographed in the main section of his Medical Flora of the United States (1823-1830) are studied for their historical and current use as medicinal agents. The results are tabulated and presented in a bar graph. The study concludes that Rafinesque was a progressive therapist whose Medical Flora is a promising guide for phytopharmacuetical prospecting with North American plants.