A Bethesda doctor has filed an ethics complaint against Maryland Sen. Brian E. Frosh over his handling of legislation that would have limited plaintiffs' awards in medical malpractice cases.

Audrey P. Corson wrote the Maryland State Ethics Commission and the General Assembly's ethics committee to allege that Frosh (D-Montgomery), a partner in a law firm that has handled scores of such cases, had a conflict of interest as chairman of the Senate committee that defeated the measure.

Frosh is a partner in Karp, Frosh, Lapidus, Wigodsky & Norwind, a Rockville firm that has represented numerous people in lawsuits against doctors. The firm has secured many verdicts in excess of $1 million.

Corson, an internist in Frosh's legislative district, said the legislation would have helped contain the soaring cost of medical malpractice insurance.

"Senator Frosh was instrumental in the demise of this bill," Corson wrote. "Senator Frosh should clearly disclose if he has, or ever has, received referral fees on malpractice cases."

Frosh said his partnership arrangement with the firm does not let him share in earnings from cases in which he was not personally involved. And to his recollection, he said, he has handled only one Maryland malpractice case in recent years.

But Frosh, who heads the Senate Judicial Proceedings Committee, also said he recognized early in the session that he could be vulnerable to allegations of a conflict. A page on his law firm's Web site listed 57 cases under the heading "Million Dollar and Other Major Cases," many of which are described as medical malpractice cases. When Frosh learned that doctors were circulating the list, his firm removed the page from its Web site.

Frosh said he consulted in February with the General Assembly's ethics adviser, William G. Somerville, who said he was on solid ground. "He said, 'Under the law, you can participate in this,' " Frosh said.

The situation highlights a recurring predicament for Maryland's part-time, citizen legislature: Many lawmakers wind up voting on bills that could have a direct effect on their professions. Typically, legislators are asked to recuse themselves from debate only if a measure would enrich them personally, rather than simply benefit their profession.

Frosh said Somerville advised him that the malpractice bill was not a concern because all trial lawyers -- not just Frosh -- could benefit from defeat of the measure.

"We've got lawyers, doctors and insurance agents in the legislature," Frosh said, "and, to some extent, all of us have an indirect financial interest in this legislation."

Frosh will head a commission appointed by Senate President Thomas V. Mike Miller Jr. (D-Calvert) to study the medical malpractice issue over the summer. He said he believes that he can be objective in that role as well.

But he added that he hopes the legislature's ethics committee will fully investigate Corson's complaint.

Miller said he thought the complaint was "some type of hardball preemptive strike by the far right wing of the medical profession."

"When you attack someone that is as decent and honest as Brian, I think it will backfire," he said. "It will just make members of the Senate rally around him."