A measure that would lessen the penalty for sick people found with marijuana if they can prove they possessed it for medical reasons eked out a key Senate committee victory yesterday.

The bill, approved 6-5 by the Senate Judicial Proceedings Committee, stops far short of legalizing marijuana for those who contend they need it, but it allows a judge to impose just a $100 fine if it is shown the drug is a medical necessity. It is similar to a bill approved this week by the House of Delegates.

The House passed similar legislation last year, but it failed in the Senate committee that gave its approval yesterday. The bill still needs approval from a second Senate committee, where half of its members were co-sponsors of the original measure.

Gov. Robert L. Ehrlich Jr. generally supports medical marijuana use but he has yet to take a formal position on this legislation.

The senator considered the swing vote yesterday was Nancy Jacobs, a conservative Harford County Republican, whose mother suffered from Parkinson's disease.

"I am not for legalizing marijuana in any way," she said, "but I do know that it helps people who are in the end of their life. If it would have helped my mother, I would have gotten it for her somehow."

At a hearing last month, senators heard from cancer patients who said the drug saved their lives, giving them relief that no prescription medicine could. They also heard from those opposed to the bill, including the Maryland State Medical Society, who said science has yet to prove the benefits of using marijuana as a medicine.

"I don't see the need to prosecute people who are suffering horribly or are dying," said Sen. Brian E. Frosh, the committee chairman and a Montgomery County Democrat. "It's an effort to be humane to those in intractable pain."

Sen. Leo E. Green, a Prince George's County Democrat, is firmly against the bill. "It indirectly legalizes marijuana -- that's basically what it does," said Green, the committee's vice chairman. "It gives a defense to drug dealers because they will now say they're caregivers."