Those 'herbs', like you mentioned, are where we get most of our modern day medicines. The reason the USDA 'warns', is that they can't regulate the dosage ...
If you check the list of each extract in the drink, you will find that out of all, caffeine is among the highest, except for one or two.
There are a few out there that will have another form of herbal stimulant, but not all do. So the buzz you daughter got, was mainly from caffeine; a 6 oz. can is equivalent to about 3 cups of strong coffee.
So ... if you daughter is not an everyday coffee drinker and use to caffeine, one of them could keep her up quite awhile!