Nancy Reagan took her fight against teen-age drug abuse to the public again yesterday, telling a White House drug conference that she is "scared to death for our children."

Mrs. Reagan hosted a day-long meeting for about 100 corporate, community and religious leaders to kick off a new Drug Use Prevention Program sponsored by ACTION, the national volunteer agency.

"I don't think ever in my life have I felt as compelled to do something about an issue as I feel about youthful drug abuse," Mrs. Reagan told those gathered in the East Room under the glare of network cameras.

About 10 doctors, community activists and businessmen addressed the group, rattling off statistics on drug abuse. Texas industrialist H. Ross Perot had the audience's rapt attention.

The U.S. drug industry, he said, does a $68 billion to $89 billion annual business. Other authorities said drug traffic in the United States is as high as $100 billion annually.

"Mothers all over this country who are finding seeds in their child's pockets--unless your kid is into gardening--take that as a very bad sign," said Perot.

The conference began at 9 over coffee and tea served from elegant china on the State floor. Melissa Gilbert, 17-year-old star of the Reagans' favorite television show, "Little House on the Prairie," was followed around by almost as many reporters as Mrs. Reagan. Her mother, Barbara Abeles, seemed taken aback when the Secret Service confiscated a gift she had brought for Mrs. Reagan. "She'll probably never see it," she sighed to her daughter.

Moments later Gilbert was surrounded by scribbling scribes. No, she doesn't use drugs. Never has.

"In the beginning, my peers used to think I was square," said Gilbert, who is the national spokesperson for ACTION's program. "Now I think kids respect me for it . . . There's almost reverse peer pressure among my contemporaries. Everyone wants to look good and feel good [so] most of my peers are staying away from drugs."

The display of drugs and related paraphernalia was expansive. Right outside the Blue Room was a case filled with uppers, downers, cocaine, heroin and several varieties of marijuana. An elaborate collection of trick soda cans, Frisbees, shoes and toy trucks was also on display to illustrate how drugs can be hidden.

Last month, the first lady visited Florida and Texas to urge support for drug prevention programs. Mrs. Reagan has been talking to community drug groups for the past two years. But her recent increased visibility on the issue reflects White House efforts to present a more issue-oriented first lady. The drug-prevention groups are overjoyed at having her support.

"We clearly can use any help she offers," said David Gurr, an ACTION policy analyst. "She said this is her number-one social priority, and it gives the cause some visibility."

After the morning briefing, guests adjourned to the State Dining Room for a lunch of sliced chicken, asparagus and wild rice served on the Johnson china. Gold wrapped Godiva mints sat on all the tables. One per person.

Following lunch, Mrs. Reagan thanked everyone for coming and speaking. She asked them to stay for the afternoon session, and she slipped out to the residential quarters.