Abstain from mallows. This is the thirty-eighth symbol in the Protreptics. Pythagoras tells us that mallow was the first messenger sent by the gods to earth to indicate to man that they sympathised with them and had pity on them. To make food of mallows would be to dishonour the gods. Mallows are cathartic.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894