It might stick to your shoes and annoy your teachers and parents, but chewing gum is good for you - and it's official!
Scientists have discovered that a bit of chewing gum makes people cleverer, because it helps you remember things and makes your brain work better.
Chewing helps you remember
The experts found that of the people tested, 35% who were given gum to chew found it easier to remember words.
But it's not clear why this happens.
It might be because chewing increases the speed of your heartbeat, so more oxygen is pumped round your body.
Or it could be because chewing gum helps your body make insulin because it thinks food is coming, which helps the bit of your brain in charge of memories work harder.
To make sure the tests were fair the scientists gave one group of 25 some gum to chew, another no gum at all, and asked a third group to pretend to chew gum even though they didn't have any.