"Mangos are in the same family as poison oak. In the tropics after I had enjoyed about a kilogram of mangos, some people said, 'Oh, don't you know about mango sickness?' It's well known in the tropics, but I think it is partly because they are sort of a fibrous fruit, and partly because if the fiber isn't handled by the right bacteria, it can cause toxin production in the intestine."
Dr. Ray Peat, in an interview "Dr. Ray Peat: Glycemia, Starch and SUGAR in context!"
Go to about the 28:30 point.