"Medicine has changed, and people often don't understand the increasing complexities," says Dr. Erwin Witkin, director of scientific relations for the Health Care Expo '85. "So we decided to get everyone together at the same time to help update the public."

By everyone, he is referring to more than 600 faculty speakers from medical institutions, health care organizations and private industry and some 200 exhibitors featuring everything from spiraling medical care costs to the latest in disease prevention. They all arrive at the D.C. Convention Center Sunday.

There will also be a host of public programs designed to educate people on current health issues. "One program will feature the problem of alcohol and drug abuse," Witkin said. "We will bring in former abusers and nonabusers from the sports industry to show kids that they can live without this stuff."

The Convention Center will be divided in to 20 centers, each focusing on a major specialty in medicine. The American Heart Association will offer demonstrations and lectures at their booth in the heart section; the National Aeronautics and Space Administration will feature space-age contributions to medicine, such as CAT scans and fiber optics; the World Health Organization will report on, among other things, international vaccine efforts.

"This is unique," says Witkin, "because this is the first health care expo that involves all of these components, and it is the public's first chance to meet all of these people in one place."

The expo will run Aug. 18 to Aug. 24. The hours will be: Sunday, 10 a.m. to 5 p.m.; Monday through Friday, 8:30 a.m. to 5 p.m.; Saturday, 8:30 a.m. to noon. Admission is $5 for one day. For more information, call 789-1600.