Records about the traditional uses of medicinal plants can be considered useful in bioprospecting (i.e., the search for new active agents or lead structures in nature). Several sources like Egyptian papyri, early modern herbals and pharmacopoeias have been studied in this respect. It is proposed to use recordings of botanically interested explorers of the 19th and early 20th centuries as well. Some of them give detailed information about traditionally used medicinal plants and analysis shows that a considerable number of these have never been scientifically investigated. Existing studies, however, are confirming the traditional uses described to a great extent. Thus, the explorer's writings should not be neglected while looking for starting points for plant screening; success seems more likely than with screening at random.