Amazonia’s traditional knowledge, especially the indigenous one, is known to treat diseases with the use of medicinal plants. This is the knowledge used to base sequential and controlled studies which aim to characterize clinical and toxic effects of the most commonly used phytotherapeutic plants by the general population. /nThis project proposes to evaluate and characterize, in a partnership between Oriental Amazon Embrapa and Pará’s State University and (Pará’s) Center of Superior Studies, the biopharmacological effects of Amazonian medicinal plants, such as copaíba ( Copaiba reticulate), andiroba ( Carapa guianensis), sacaca ( Croton cajucara) and babosa ( Aloe vera), which are known to have therapeutic properties by the general population, lay literature and botanic books./nThe hopes are to determine with the results, basic therapeutic action and toxicity of each studied plant. The determination of these results will help to guide rational use of studied substances, as well as ground studies which search for new medicines.