AIM OF THE STUDY: To asses the scientific value of the practical medical fragments found in the Cairo Genizah (10th century), as a useful source for ethnopharmacological purposes (in exposing rare and usually inaccessible original medieval practical knowledge of medicinal substances to present-day researchers), and to reconstruct the practical drugs and their uses. MATERIALS AND METHODS: A methodology distinguishing between theoretical (about 1500 fragments) and practical medical knowledge (about 230 fragments) was created and used. The information regarding the practical medicinal substances was extracted from prescriptions (140), lists of drugs (70) and few letters of physicians. RESULTS: The reconstructed lists of practical (278) and theoretical (414) drugs allow us to recognize and quantify the gap between them in medieval times (136). CONCLUSIONS: We propose that the data obtained from ancient prescriptions is comparable to ethnopharmacological surveys. The finding of plants such as myrobalan, saffron, licorice, spikenard and lentisk, all of which have scientifically proven anti-microbial/bacterial and anti-fungal activity, sheds a helpful light on the medical decision-making of the medieval practitioners in respect of the plants they applied as drugs. With the wealth of information meticulously assembled from these time capsules we expect to make a significant contribution to contemporary efforts at locating modern drugs in ancient roots and gauging their feasibility.