Before a company runs an ad, it has to have a "reasonable 
basis" for the claims. A "reasonable basis" means objective 
evidence that supports the claim. The kind of evidence 
depends on the claim. At a minimum, an advertiser must have 
the level of evidence that it says that it has. For 
example, the statement "Two out of three doctors recommend 
ABC Pain Reliever" must be supported by a reliable survey 
to that effect. If the ad isn't specific, the FTC looks at 
several factors to determine what level of proof is 
necessary, including what experts in the field think is 
needed to support the claim. In most cases, ads that make 
health or safety claims must be supported by "competent and 
reliable scientific evidence" -- tests, studies, or other 
scientific evidence that has been evaluated by people 
qualified to review it. In addition, any tests or studies 
must be conducted using methods that experts in the field 
accept as accurate.