Minnesota is the only state to limit gifts drug companies can give doctors, but its cap of no more than $50 a year in free food or other presents may catch on elsewhere. In September, New Jersey created a task force to examine ways to set similar limits. The freebies are seen as unduly influencing prescription-writing and raising costs.

Minnesota's ban does not stem from a direct action taken by the legislature. Rather, it hinges on one state official's different interpretation of a 1993 law. But since that interpretation was made two years ago, drug representative visits to Minnesota doctors have dropped at twice the national rate of decline, according to ImpactRx, a firm that tracks pharmaceutical marketing. Moreover, at least 20 clinics in one of the state's largest private health systems immediately banned routine visits from drug representatives, and a growing number of hospitals and doctor's offices are following suit.

While other states consider similar limits, several medical schools have already barred the gift giving. Stanford University, citing concerns that the gifts were influencing medical training and affecting patient care, became the first in 2005. Several others have done likewise, including some public universities. The University of Connecticut is the latest to consider such a move.

For half a century, pharmaceutical reps have been paying doctors visits to educate them about new medications. But the number of visits has grown, as has the largesse of the gift-giving. Last year, according to an article in the Journal of the American Medical Association, the industry spent about 90 percent of its $21 billion annual marketing budget on doctors.