I don't know if it's common, but I have heard of it.

Kids and, well, very tall kids too.

I've heard of MSG giving people headaches, but nothing about making them "nutso". I think I'm gonna do some Googling......

Here's something interesting: http://www.brighthub.com/health/diet-nutrition/articles/26394.aspx
So is this: http://www.healthy-holistic-living.com/msg-reaction.html

Looks like MSG sensitivity can manifest itself in several different ways, including hyperactivity.

MSG = mono sodium gluatamate. Glutamate is a neurotransmitter and it is considered an excitatory neurotransmitter. See http://en.wikipedia.org/wiki/Glutamic_acid

So yeah, hyperactivity could happen.

As an adult, MSG triggers migraines in me, so I avoid it. Since I don't eat it, we don't have stuff around the house for the kids to consume, either.

I know at my behavior treatment facility, the cottages will only order takeout from the Chinese restaurant that is MSG-free. The youth leaders have said that the clients get squirrely if they have stuff with MSG, too, so your girls aren't the only ones to whom this happens.

Its really on a kid by kid basis. SF isn't affected at all so it isn't an issue. Most kids who do react get headaches and nausea. Can't recall hearing kids getting wired.

MSG: There's a reason they're taking it out of soup. I also suspect artificial colors, particularly Blue #1 and Red #40. Don't get me started on high fructose corn syrup, either. For a while when K was little, he didn't get much pre-packaged food at all, and I wish I'd known more about nutrition when G was little.

Sometimes kids do just have a "go nuts" day, but it is worth keeping an eye on the MSG.

As has been said, check some of the other prepared foods in your house - even though MSG has been being eliminated little by little over the last few years (mostly for sensitivity issues and sodium level issues), it is still out there.

There is MSG sensitivity in the family: It makes me miserable, and I remember hearing mother make a comment on it once when I was in college. One manifestation is general agitation and anxiety. I made beef barley soup on Monday and forgot to check the canned broth for MSG. By Tuesday I was growly and anxious, and by Wednesday had a honker of a migraine. I dug one of the cans out of the recycle bin and the broth was rotten with it. Do not eat Campbell's soup. Swanson's is the way to go.

If you have a take-out menu from the restaurant, check to see if they say anything about MSG. Most of the Chinese and Thai places we eat state that they don't add MSG. I don't take that as "No MSG at all in our food" because it could easily be part of a sauce or base that they buy, but not having their cooks adding it is something.

I know MSG makes me feel sick-my mouth goes numb. I haven't heard of it affecting kids though.