Tech: The incredible story of how hatmakers really did 'go mad' 300 years ago

The expression 'mad as a hatter' is based on the fact that hatters used to unknowingly poison themselves in the process of hat-making.

The expression 'mad as a hatter' is based from the real-life behavior of hatters from the 17th century. It turns out that the process they used to make their hats was poisoning them and driving them insane. It wasn't until 1941 that hatters discovered what was causing them to behave so strangely.

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The expression 'mad as a hatter' is based on the fact that hatters used to unknowingly poison themselves in the process of hat-making. Read Full Story