It appeared only once, in a medical journal mailed to only 1,115 doctors. But it has haunted Hoffmann-LaRoche for a decade, rather like the illegitimate offspring of an affair it would rather forget.

They call it simply "the college girl," an advertisement for Librium that ran in 1969 in a journal aimed at college physicians. It was a year of campus unrest and the ad featured of troubled-looking young woman, wearing a duffel coat and carrying books, underneath the headline: "A Whole New World . . . of Anxiety."

The ad reads: "Exposure to new friends and other influences may force her to reevalute herself and her goals . . . Her newly stimulated intellectual curiosity may make her more sensitive to and apprehensive about unstable national and world conditions . . . Today's changing morality and the possible consequences of new freedoms may provoke acute feelings of insecurity.

"To help free her of excessive anxiety . . . " the ad urged doctors on college campuses to prescribed librium as part of their counseling.

"In the early 1970s Roche was accused of running Librium advertising (directed) to the college students," said Robert DeVanna, the firm's advertising director. And today, critics of drug advertising often cite that single Librium ad as the worst of the company's ads for a different drug, Valium.

In 1978, Hoffman-LaRoche spent $4.8 million to advertise Valium, and that, said DeVanna, was down 27 percent from the previous year. That amount goes for a product that accounts for an estimated 40 percent of the firm's $1.4 billion to drug sales last year.

Valium advertising, he said, is not intended "to increase sales." Our goal is to optimize the use of the product -- and that's a fact. As far as Valium is concerned, we communicate as we do because it's used as widley as it is, and it would seem to be a responsibility and an obligation to communicate with physicians in direct proportion to the use of a pharmaceutical product."

Advertising is not intended to just remind physicians of the product, DeVanna said. "As a matter of fact it's a Roche philosophy not to use the type of advertising which just registers the name, that borders on reminder advertising, and we don't believe in it."

Nevertheless, at the 1978 convention of the National Medical Association, held here, in Washington, every doctor was given a blue, simulated leather, zippered portfolio with a label inside with the word VALIUM in inch-high letters and the forms the drug comes in.

Asked about the briefcase, DeVanna replied that he meant that when Hoffman-LaRoche spends money on full-color print advertisments, it wants to get more than the product name across.

DeVanna pointed out that Valium's advertising budget is smaller than those for two other minor tranquilizers. But he didn't mention that Valium is much better known than the other two products and has the lion's share of the tranquilizer market.

Though Valium was originally advertised simply as a drug to fight anxiety and relax muscles, its advertising now implies that it is a treatment for heart disease, ulcers and several other conditions.

"In the anxious post-MI (heart attack) patient, these parameters may be improving," reads the introduction to the first page of such an ad, over a photograph of a stethoscope and cardiogram strip. "But these may not," it continues, showing that a doctor has written "feelings of tension, difficulty in falling asleep, loss of interest, and inability to relax" on the patient's chart.

And another ad, with a similar layout, begins, "in the anxious ulcer patient," and then points out that although the patient's ulcer may have healed, he may be anxious, and valium will help him relax.

According to critics Hoffmann-LaRoche is now advertising Valium this way because the firm's patient on its tranquilizer gold mine expires in four years, and it wants to expand the market while it can.

Not so, says DeVanna. All the firm is trying to do is make doctors aware of Valium's many benefits. Hoffmann-LaRoche does not want to increase the sales of the product; it wants to "optimize its use."