Sleep paralysis, as it is known today, was one of the most remarked-upon maladies in premodern medicine. The feeling of being choked during sleep was usually seen by physicians as being caused by an abundance of melancholic humors. Others interpreted the experience as a supernatural attack. However, the distinctions between medical and “superstitious” remedies against nightmares were rarely so clear cut, especially given the belief that demons were able to manipulate the bodily humors. In this article I will chart the various substances—plant and stone—that were traditionally believed to assuage the symptoms of the nightmare. I will examine how “hot” herbs, such as peony, and minerals with occult heating properties, such as gagate, could rebalance the dangerously cold and heavy vapors that provoked a nightmare attack. It will be seen that even seemingly “magical” apotropaic practices were entirely rational within the milieu of humoral theory.