First Lady takes her anti-drug campaign on the road

''I've never seen a First Lady eat before,'' exclaimed a Jonesboro, Ark., homemaker gawking over a playground fence at Nancy Reagan, who, in her electric-blue suit and perfect coif, was eating a brown bag lunch with local teen-agers.

Obtuse as the observation may seem, this kind of curiosity and awe over the First Lady is key to the kind of public relations used in Mrs. Reagan's anti-drug campaign which took her this week to Montgomery, Ala.; Jackson, Miss.; Little Rock, Ark.; and Jonesboro.

The encounter with Mrs. Reagan is likely to burn for a long while in the memories of the Arkansas homemaker and hundreds of others who come in contact with the heady fringe of world power as the First Lady sweeps into town with her traffic-stopping entourage of no-nonsense Secret Service guards, serious staff, and trail of dogged news media.

By mere association, this air of importance is lent to the programs Mrs. Reagan visits.

''This makes us look important,'' beams Martha Lott, a high school senior from West Point, Miss., who, along with nine other members of DREAM (Drug Research and Education Association of Mississippi), chatted with Mrs. Reagan for a half hour before blazing television lights and cameras at the governor's mansion in Jackson. ''It gave us an opportunity to get a lot of attention for our group. We'll take it back home and just the fact we talked to the First Lady , people will listen to us.''

A slightly more cynical approach was taken at Little Rock Central High School , where black students, picketing Mrs. Reagan's arrival, protested social program cuts and tuition tax credits for private schools.

''I think it shows she cares. She didn't have to come all the way down here, '' said one Central High senior, a long-haired girl with perfect makeup. But, she added, ''Just because the First Lady says to stop wouldn't make me quit (using drugs) . . . she hasn't ever been into drugs. How does she know what she's talking about?''

This comment was made before Mrs. Reagan appeared with Carl Eller, the former Minnesota Viking lineman and ex-cocaine addict whose story of his plummet to the depths of drug addiction hushed even the most persistent wisecrackers among the students.

Granted, Mrs. Reagan doesn't come off as a hardened expert. Her speeches to and conversation with parents and students are low key, and she substitutes the concerns of a parent - which she says is her qualification on the issue - for rapid-fire statistical evidence of the spread of drug abuse.

But her efforts are not lost on Americans, who have increased by 2,000 the number of parent anti-drug groups since Mrs. Reagan started her campaign in 1981 , said Dr. Carlton Turner. The Reagan administration's emphasis has been on drug prevention programs where volunteer work, which costs nothing, can be utilized, he explained.

Mrs. Reagan says she doesn't think her campaign for more participation in drug prevention programs runs contrary to her husband's social program cuts, which reduced federal expenditures for drug programs from $1 billion in 1981 to

''It doesn't take money to buy love and awareness and to spend time with kids ,'' she said. That's as far as she'll go, though, in answering questions regarding her husband's politics. Her graciousness is tried and a sense of her vulnerability is exposed each time reporters attempt to quiz her on her husband's politics - a practice that threatens to eclipse the whole reason for the trips she makes. (A meeting with the editorial board of the Jackson Daily News and Clarion-Ledger this week turned into just this sort of session between reporters, Mrs. Reagan, and her staff.)

What the press apparently doesn't grasp, Laurel, Miss., high school senior and DREAM member Terry Weems does. Asked if cuts had affected drug abuse programs in his area, he said the only thing he noticed was that ''my lunch went up to a dollar . . . but that's not her fault, that's Ronald's.''