Aproposed deal between a family doctor group and an arm of a tobacco conglomerate has wound up on the ash heap.

Fleischmann's, producer of a no-cholesterol margarine, has withdrawn from nearly completed negotiations with the American Academy of Family Physicians for a joint advertising campaign to promote cholesterol testing. Fleischmann's is part of Nabisco, purchased in 1985 by the R.J. Reynolds tobacco company to form RJR/Nabisco.

The $1 million arrangement was the subject of heated debate by the family physicians at a convention in San Francisco last month, with one faction contending that themoney was tainted by the tobacco connection.

Dr. Robert Graham, executive vice president of the Kansas City-based academy, said Mark Schoenholz of Fleischmann's, with whom he had been negotiating, was disturbed by the "internecine" dispute within the academy over the deal's propriety. Graham said he was told Fleischmann's did not want to be in the middle of a running, open battle. A Fleischmann's spokeswoman declined any comment other than, "There will be no agreement."

The 59,000-member academy has long been one of organized medicine's antismoking leaders. But in San Francisco, the academy's policy-making Congress of Delegates, despite strident opposition, cleared the way for the deal to proceed. Though it banned the academy from dealing with parent tobacco firms, it permitted agreements with subsidiaries such as Fleischmann's.

Dr. Brent Blue of Jackson, Wyo., and other members of a 10-year-old health activist group called Doctors Ought to Care -- made up largely of members of the academy -- were the most vocal opponents of the arrangement.

But Graham had defended the deal. He said the $1 million ad campaign in women's magazines, paid for by Fleischmann's, was a rare opportunity to reach many patients with an important health message. It would have asked readers to have their cholesterol checked by "your family doctor." Moreover, he adds, Fleischmann's agreed to the academy's stipulation that the ads also point out that cigarette smoking, as well as high cholesterol, is a cardiovascular disease hazard.

Blue said he was pleased that the deal had fallen through. "But," he added, "I would have preferred that the academy make the choice instead of having it made for them."