In "New Spring," Lan thinks to himself one time, "As sure as peaches are poison, you cannot trust an Aes Sedai."  What does that mean?  Is this a Sword of Truth type thing where fruits are poisoned, or is it some expression that I don't understand?

Peaches became poisonous sometime after the sealing of the Bore. That is all we know.

 

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In WH there's the first mention of this. RJ just decided to make peaches poisonous as another aspect of this world that makes it different from our own.

It's one of the mutations in this world. Like cats in the Two Rivers have six toes instead of five. It's just flavor text.

Someone revitalized the old topic so I'm locking this. Look to 'the really important question no one has discussed' thread.