The CBS show "Numbers" is one example. "Numbers" writer David Harden called, saying he was pursuing a plotline about black market profiteering in human organs. TV writers like the topic because of its dramatic potential and persistent hold on the public imagination: Who hasn't heard the urban myth about the man who meets a hot woman in a bar and wakes up in a bathtub full of ice?

Health officials, however, hate it. They say there is no black market in organs in the United States, and dramatizing the idea may dissuade Americans from becoming organ donors.

But the program took Harden's call and convinced some experts to talk to him. One in particular was skeptical of the plot idea at first, Harden recalled, but answered every question.

The resulting show, which aired in January 2006, was about an international black market that provided detailed information on how the national organ matching program works. Health officials deemed it a success: In a subsequent online survey of about 160 people who said they were not organ donors, 10 percent said they had decided to become donors after watching the episode.

Another success occurred a few years ago with the Fox show "24."

The show was interested in this scenario: Terrorists release a biological agent in a hotel air conditioning system, making people sick in a matter of minutes and killing roughly 2,000 people within a few hours. They concocted a genetically engineered "Cordella virus" to do it, and wanted government officials to be able to wave an electronic device that could instantly detect the virus in the air.

They consulted CDC officials, who said there are no such devices. The CDC also suggested that health officials might try to deal with such a situation by isolating the ill from the well, perhaps reducing the contagion's impact, said Dr. Mitchell Cohen, director of CDC's Coordinating Center for Infectious Diseases.

The writers took the tip, and the final death toll fell to under 800. "We saved 1,200 virtual people," said Cohen, who consulted with the "24" writers and did an on-camera interview for the DVD boxed set of the series.

CDC officials make time for Hollywood meetings, because they know what's on screen can be influential. In a 2000 CDC-sponsored survey, more than half of TV viewers said they trust health information on prime-time shows to be accurate, and about one-quarter said prime-time television is one of their top three sources of health information.