This article examines Dante da Maiano's response to Dante Alighieri's dream in the Vita Nova, often seen as a mocking reply to the young poet's vision. Building on Bruno Nardi's reinterpretation (1959), which suggests a medical explanation rather than mere ridicule, this study analyzes the sonnet through medieval physiological and medical theories. Dante da Maiano's diagnosis, influenced by Galenic and Aristotelian thought, links the poet's delirious dream to harmful vapors rising from the testicles to the brain. These vapors, produced by excessive heat and imbalance in the reproductive organs, were thought to cause mental disturbances by drying out the brain, a common medieval explanation for lovesickness. The article highlights the conceptual connection between the brain and the testicles, recognized in medieval medical theory, especially in the works of Galen and Albert the Great. By situating Dante da Maiano's response within this scientific framework, the article reinterprets his advice-like washing the testicles to mitigate harmful vapors-as a serious medical recommendation rather than as derision. This perspective enhances our understanding of the interplay between physical health and mental states in medieval thought, offering fresh insights into Dante's dream and its broader medical and philosophical implications.