Marketers of nutritional supplements often complain that they do not know what the FDA wants. Even after the agency sends a warning letter about misleading claims and advertising, its staff does not explain what would fall within the rules. That's the reality; the FDA will tell you what's wrong, not what's right.

Through warning letters, the agency provides insight into how a marketer can fall afoul of the rules. Companies that examine why their competitors get chastised can apply the lessons to their Web sites, catalogs, labels and the like.  Washington attorney Ivan Wasserman looked at the 73 letters issued in 2009 (way, way up from 44 in 2008) and found that 72 related to claims on Web sites. Six involved claims made in metatags.

Lesson #1: The FDA is surfing the Web, checking not just product descriptions and benefits, but Googling for questionable SEO/SEM.

Wasserman's list would rank the letters by claim problems in this order:

• Drug and disease claims: 72
• H1N1 virus claims: 37
• Other drug and disease claims: 20
• Heart disease and cardiovascular claims: 11
• Diabetes claims: 8
• Cold and flu claims (not H1N1): 8
• Cancer claims: 8

Lesson #2: The medical emergency that makes the most headlines gets the greatest scrutiny. In 2009, that was H1N1.

The FDA also sent 12 warnings letters related to claims made on labels and product labeling. Some of these may have echoed what was published on Web sites as manufacturers compounded their marketing errors.

Lesson#3: The FDA reads labels in the stores and on packages sent by mail. Adding an asterisked disclaimer to language on a label is no protection.

The FDA lived up to its announced commitment of greater enforcement and more scrutiny of the supplement industry. The agency could top the century mark in warning letters this year. Companies that have not recently reviewed their sites and labels would be wise to do so now before the mail carrier brings bad news.