Myth: The Heat of Hot Peppers is in The Seeds.

This myth is false, but it's also true in a way. The heat in hot peppers comes from a chemical called capsaicin, and most of the capsaicin is contained in the pith, the white material that holds the seeds in place inside the pepper. The seeds actually contain very little capsaicin. So, you could remove just the seeds from a pepper and affect the heat very little if at all. But because most people remove the pith along with the seeds, they get the desired result of lowered heat.

Note that the pith does not contain all the heat—the flesh contains some as well.