A just-filed lawsuit has some people wondering: How much caffeine would be necessary to kill someone?

The lawsuit claims that a 14-year-old girl drank two 24-ounce cans of a so-called "energy drink" before suddenly dying. Energy drinks combine higher-than-usual amounts of caffeine with other types of stimulants and vitamins.The coroner's report says that "caffeine toxicity" was a factor, though possibly not the only one.

I drink a lot of diet cola. You may drink a lot of coffee or tea. So how much caffeine is too much?

Well, Popular Science.com says the editor-in-chief of the Journal Of Caffeine Research [and surprisingly there is such a journal] thinks 10 grans of caffeine in a short time would do the trick. A 2005 study on two caffeine-related deaths in New Mexico says the figure would be just five grams [the amount in about six gallons of McDonald's coffee].

Complicating the matter even further is the fact that caffeine overdose is almost always just a single factory in a death [other items blamed include heart disease, exercising strenuously  or combining caffeine with alcohol]. An app called Death By Caffeine argues for six grams of caffeine per hundred pounds of body weight, although the app is said to be "for entertainment purposes only".

Obviously some of us take in too much caffeine. And lesser amounts would certainly be better for most of us. But it looks like it'd be easier to beat yourself over the head with a rock.