Chicago Mayor Jane Byrne yesterday branded as "gutter tactics" the suggestion by a Democratic foe that she has been under some form of sedation in recent months. But George W. Dunne, president of the Cook County Board, said it was all a misunderstanding and he had never intended to imply the mayor was on drugs.

"Sedation means calm, docile. You can acquire that in many different ways, even through spirituality," Dunne said. "That's a ludicrous thing. I don't think this merits an apology . . . ."

"It is unfortunate, but it just seems women candidates are more susceptible to charges like this," Byrne said. "Four years ago . . . it was that I was menopausal. As a woman candidate, I am getting used to the low road with some individuals."

Dunne, who gained power under Richard J. Daley, supports the late mayor's son, State's Attorney Richard M. Daley, against Byrne in the Feb. 22 Democratic mayoral primary.

Dunne was ousted last year as county Democratic chairman and replaced by a close associate of Byrne, Alderman Edward Vrdolyak. Dunne also has accused the mayor of being behind efforts by county board members to usurp his powers as board chairman.

During a taping Thursday for a television program to be aired tomorrow, Dunne was asked about Byrne's motives in seeking control of the county board.

"I'm not a psychiatrist, and I can't put my finger on the evil characteristic that triggered this," said Dunne. "I would say this: I'm firmly convinced of the fact that the mayor is under some form of sedation and has been for the past three or four months."

He said the comment was based on watching the mayor on television.