I recently published in this journal (41 [1985] 341–65) a guide to the medical MSS mentioned in Iter Italicum III. That volume had no index. The first two volumes of the Iter (London—Leiden 1965–67) do have indices, and it might be thought that the present guide is superfluous. But it is quite impossible to get from the indices an adequate idea of the whole body of medical literature listed in Kristeller's magnificent inventory. The Iter is devoted, above all, to theology, philosophy, law, literature, history, musicology, mathematics, and astronomy. Medicine, is, however, not neglected. I hope the present guide will stimulate research into the various genres of medical writing in the Middle Ages and Renaissance. We still have too few editions of medical texts from these two periods, which are really critical and based on all available MSS. We need more studies of plague tracts, consilia, receipts, and medical correspondence. Minor as well as major figures should be studied.