Marjorie Zucker, who died Tuesday at 86, was a physiologist and co-discoverer of the convenient fact that aspirin inhibits blood coagulation.

The discovery pointed the way to so-called “aspirin therapy,” whereby small doses, typically children’s aspirin, are taken daily by millions of people at risk of stroke and heart attack.

As a Ph.D. scientist (and not an M.D. or clinician), Zucker didn’t help develop the actual therapeutic regimen; in fact, the discovery was accidental.

By the time she discovered aspirin’s ability to thin blood in 1968, Zucker was already an authority on the platelets responsible for blood clotting, having published the authoritative book “The Physiology of Blood Platelets” in 1965, with co-author Howard Zucker. The book was the first comprehensive statement on platelets, whose role had only recently become clear, thanks in part to Zucker’s groundbreaking research. Her work showed, for instance, that the normally disc shaped platelets change shape, becoming round and spiky while adhering together to form a clotting plug.

As her research continued, she noted that some blood samples, taken from volunteers at her New York Medical Center laboratory, showed far less tendency to coagulate than others. A brief inquiry showed the differences were entirely dependent on whether the person donating the sample had recently taken aspirin. Her subsequent investigation showed that the effect happened in part because aspirin inhibited the release of platelet serotonin.

Zucker grew up on the Upper West Side. Her father, Murray Bass, was chief pediatrician at Mount Sinai Hospital, and an expert on childhood diseases. In 1938, he co-founded the Society for the Right to Die. Zucker attended Vassar, and was married while still an undergraduate to Howard Zucker, then in medical school, who had been a childhood chum on visits to the American Museum of Natural History. He became a psychiatrist. The two shared left-wing politics, had four children, and also co-edited the volume “Medical Futility” (1997), a book of readings about the uselessness of intensive intervention in extreme cases.

Zucker received her Ph.D. from the Columbia College of Medicine in 1944, and became an associate professor at the New York University School of Dentistry, where she was a teacher and researcher. Her teaching duties ended when she left in 1954 in a dispute over being paid less than the men on the faculty. She was immediately hired by the Sloan Kettering Institute, and from then on devoted her career to research. In 1963, she returned to NYU, to take charge of her own laboratory at its Medical Center.

As for having an unusually visible career for a woman in the 1940s and 1950s, her husband, Howard Zucker, said, “She just took it for granted. Her father expected her to do anything she wanted.” Friends admired her outspoken acerbity, which so manifested itself in politics that she professed astonishment that she was allowed to travel outside the country during the McCarthy era.

The family summered Sharon, Conn., where Zucker indulged her love of bird watching, gardening, and tennis. It was while convalescing from a tennis injury – a broken ankle – that she hit on an inspired method of dealing with a common gardener’s bane, the annual deluge of summer squashes. The result was “The Squash Family Cookbook,” a slim volume of 80 recipes ranging from yellow squash relish to zucchini souffle to zucchini omelet for two. Craig Claiborne deemed it “modest but gratifying.” All proceeds went to the School for Musical Education on West 94th Street, a favored haunt for her children.

Zucker also edited “The Right to Die Debate: A Documentary History” (1999), a sourcebook on a controversial issue. She served as director and on the board of the Right to Die Society.

Her own last days were dramatically consonant with her life. She endured multiple health problems in recent years, but when treatment for thrombocytic disease, a blood malady affecting her platelets, grew too onerous, she chose to discontinue treatment, and died in her home.

Marjorie Bass Zucker

Born June 19, 1919, in Manhattan; died March 7 at her home on the Upper West Side of a blood disorder; survived by her husband, Howard Zucker; her children, Andrew Zucker, Ellen Harrison, Joan Zoekler, and Barbara Zucker Pinchoff, and eight grandchildren.