An explosion of printed books and treatises on medicine in sixteenth-century Europe inspired new intense debates about medicine and its relation to the divine order of nature. Both trained and untrained healers engaged in close observation of the natural world, but good doctors did not rely solely on empirical observation—they also took into consideration invisible forces such as the soul. Physical symptoms of illness were notoriously deceptive. Trained healers had to understand subtle differences between different signs of illness and interpret those signs in relation to larger patterns. Much of the debate about medicine in early modern Europe centered on the iconoclastic figure of Paracelsus, an itinerant healer and alchemist who challenged Galenic orthodoxies. Shakespeare’s All’s Well that Ends Well includes the healing of the King of France by the virginal Helen using “receipts” that align in several ways with the Christianized practice of Paracelsus. Shakespeare frames the central act of healing in his comedy as a divine miracle, yet in concealing details of the actual cure from the audience, the play raises further questions about the relation between medicine, science, and the ordo creationis. Like Shakespeare’s comedy, Macbeth also illustrates challenges of empirical observation and medical diagnosis, focusing skeptical attention in particular on modes of unmediated vision. Where Simon Forman understood his own medical knowledge, astrological predictions, and alchemical cures to be expressions of divine will, the Doctor in Macbeth turns to God only when he is unable to treat her. For Shakespeare as for Galen and Paracelsus, however, acts of medical observation serve theological ends.