dr. delaney, are concerned. >> over the last five years, what we've seen is a marked increase in the number of people who are ending up in emergency departments because of their energy-drink use. and what we're seeing -- people with insomnia, nervousness, agitation, serious headaches, and in very advanced cases, seizures. >> energy drinks are big business -- $20 billion in sales a year. a lot of those buyers are teens, and they could be buying big trouble. >> energy drink is healthier. >> i say an energy drink. >> energy drink because it gives you energy, and you can get up and exercise and do whatever you need to. >> many kids don't realize that all that caffeine in energy drinks can be bad for them. we're not saying it's fine to drink soda. the point we're making is, if you think that energy drinks are safer than soda, you're wrong. according to nutrition specialist dr. deb, kids and teens should not take in more than 100 milligrams of caffeine per day. that's about how much caffeine is in a regular cup of coffee. >> in this can, it has about 154. and you also notice that there's no re-se