St. Catherine of Siena suffered from an extreme form of holy fasting, a condition classified as anorexia mirabilis (also known as inedia prodigiosa). Historical and medical scholarships alike have drawn a comparison between this primaeval type of anorexia with a relatively common form of eating disorder among young women in the modern world, anorexia nervosa. St. Catherine’s condition was characterised by a disgust for sweet taste, a condition also described in anorexia nervosa, and characterised by specific neurophysiological changes in the brain. St. Catherine’s case may be considered one of the oldest veritable descriptions of altered gustation (dysgeusia). Moreover, a more compelling neurophysiological similarity between anorexia mirabilis and anorexia nervosa may be proposed.