It does indeed mean "I'm really hungry" but for a lot of people it means they are very hungry because they have smoked marijuana. It's like a sudden, almost uncontrollable desire to eat. Usually people eat junk food to satisfy the munchies, and a lot of it. A whole bag of chips, a package of donuts, and nacho chips with cheese. Maybe a few hot dogs just for good measure. : ) For those who haven't smoked marijuana, it just means a strong hunger that requires some junk food to satisfy. You wouldn't go to your friend's house for dinner and say, "Mmmmm. I've got the munchies and that chicken dinner looks great." Well, some of you would, but that's another story. ; )

"have the munchies" as in "I have a bad case of the munchies" means that I'm not really hungry, but I need something to nibble on anyway.

Thanks,everyone! Now I've got the usage of this expression. As I don't eat snacks very often, I don't have a bad case of the munchies! Hard to award the crown to one individual. You are all the best in my heart.

When people are coming down after taking some drugs they feel hungry so they say "I have the munchies".

It is another way of say "I'm always very hungry" or simply "I'm hungry" It's commonly known, but not used much. The only person I know who says "I have a bad case of the munchies" is my Dad! Haha...