Coffee and Caffeine FAQ

The answer to that is it depends on the country. A few examples of laws related to caffeine content for food and drinks include the following:

In the United States there is a limit of 65mg of caffeine per 12 liquid ounce in beverages. This may only be for carbonated beverages. (What we call coke here in the south and my northern friends like to call pop.) There is also a limit of 200mg in pills such as Vivrin. For more info on caffeine contents in drinks check out  High Caffeine Pop from 'Energy Drinks' Revealed. Also check Ask Erowid for more specifics. 

Here is the FDA regulation text:

[Code of Federal Regulations]
[Title 21, Volume 3]
[Revised as of April 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 21CFR182.1180]

[Page 462]
 
                        TITLE 21--FOOD AND DRUGS
 
CHAPTER I--FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN 
                          SERVICES (CONTINUED)
 
PART 182--SUBSTANCES GENERALLY RECOGNIZED AS SAFE--Table of Contents
 
            Subpart B--Multiple Purpose GRAS Food Substances
 
Sec. 182.1180  Caffeine.

    (a) Product. Caffeine.
    (b) Tolerance. 0.02 percent.
    (c) Limitations, restrictions, or explanation. This substance is 
generally recognized as safe when used in cola-type beverages in 
accordance with good manufacturing practice.

This text is available at the GPO web site. Essentially what this means is that for a drink or food to fall within the FDA's guidelines 68 mgs per 12 oz is acceptable. Some drinks do have more. I'm not sure how they manage to get away with this. My guess is that it has to do with the caffeine being "natural" coming from one of the herbs used in the drink. It has also been suggested that some of these products may me nutritional supplements at least from a legal standpoint. Supplements (vitamins and such) have a much lower oversight than food and drugs. Some of these drinks are imported. That may have an effect on legal limits. I'm really not sure. It has also been suggested that some of these companies may be simply ignoring the regulations. I have a tendency to discount the last possibility. My guess is that if companies are "ignoring" the regulation that if they get investigated they will claim one of the other reasons allows them to have higher caffeine contents.

Australia has a limit of Australia 145mg of caffeine per liter.

In parts of Northern Thailand it is completely illegal. It was outlawed as a precursor to meth.