Dr. Gorovitz was part of a 1994 report on assisted suicide by the state’s Task Force on Life and the Law, which decided that the law should not be changed. Still, he said that, without expressing his own opinion on the topic, it might be ripe for review because of experience with assisted suicide in other states and countries and because of advances in medicine.

The plaintiffs — three patients, four doctors, a nurse and End of Life Choices New York — are suing the state attorney general, Eric T. Schneiderman, and the district attorneys who are charged with upholding the law in Westchester, Monroe, Saratoga, Bronx and New York Counties, where the plaintiffs live and practice.

Sara Myers, one of the patients, has amyotrophic lateral sclerosis, known as Lou Gehrig’s disease. She uses a wheelchair. Her arms are paralyzed, her breathing and talking are compromised, and though she can still swallow, she has to be fed.

Ms. Myers, 60, did not know precisely when she might want help dying. “The line in the sand is constantly moving,” she said in an interview. But she added, “Knowing you have a choice means you don’t have to use it.”

One of the physician plaintiffs, Timothy E. Quill, became a pioneer in the movement when he published an article in The New England Journal of Medicine in 1991, describing how he prescribed a lethal dose of sleeping pills for a leukemia patient. A grand jury declined to indict him.

He challenged the New York law on constitutional grounds, and the case went to the United States Supreme Court, which rejected the challenge in 1997. The lawsuit to be filed Wednesday does not raise any federal issues.

Dr. Quill, who is head of palliative care at the University of Rochester Medical Center, said he recently had a patient whose bones were breaking from advanced cancer, and consciously stopped eating and drinking. “It took him about 10 days to die,” Dr. Quill said. “You have to be incredibly disciplined to do it.”

On the legislative front, State Senator Brad Hoylman, a Manhattan Democrat, has proposed a law that would permit doctors to prescribe lethal drugs to terminally ill patients and is seeking co-sponsors. Mr. Hoylman has said he was inspired by Brittany Maynard, 29, a California woman with terminal brain cancer who moved to Oregon so she could die under that state’s law. Through videos posted on YouTube, she became a public face of the “death with dignity” movement, and died in November of an overdose of barbiturates at her home in Portland.