Oprah Winfrey, the popular host of television's most-watched daytime talk show, broke down Wednesday while taping a program about recovering from drug abuse and admitted that she had smoked cocaine in her early twenties. The show will air nationally today. The program, taped in Chicago, dealt with the subject of women who have had drug problems. Four mothers were the guests.

Deborah Johns, a spokeswoman for the show, said yesterday that Winfrey, who turns 41 this month, would have no comment, adding only that on the program, "Oprah made a spontaneous admission to mothers battling drug addiction that she had also used drugs. ... Oprah's words on the show are the best expression of how she feels. Please watch the show." She declined to provide a transcript of the program.

Winfrey's admission came after a discussion with one woman, identified only as Charmaine, who said she currently smokes crack cocaine but isn't sure whether she is an addict because she is still functioning in her daily life. Another guest, Washington Post reporter Patrice Gaines, who has written a book about her own troubled life, said yesterday that she commented that during her own period of drug abuse, she had been "addicted to the man, not the drugs" {Related story, Page B1}.

According to Gaines and another guest, Kim Davis of Tampa, Winfrey started to cry and told Charmaine she could understand her situation, adding, "I did your drug." She said her drug abuse had occurred during a relationship with a man.

Winfrey did not mention the drug by name, but Johns said last night that Winfrey had "smoked cocaine 20 years ago." "It threw me completely off guard," said Davis, a recovering addict who is seven months pregnant and has been receiving treatment from a Tampa program called Sisters in Recovery. "You would never dream she'd had a problem with drugs. ...

"She said she was involved with a man and she did drugs when she was with him. When he was gone the drugs were gone," Davis said. "It was weird. I just saw this woman I've admired so much. And she's been where I've been and she pulled out of it. I'm 35 and I've done nothing for most of my life but get high. She got away from it. It gave me hope." Davis said it also made her sad. "With her to make an admission like that on TV, they're going to butcher her. They judge drug addicts really hard. ... I don't know if I was more shocked that she had done it or that she had admitted it on television. ... I had a hard time admitting it and I had nothing to lose. She's got a lot to lose."

According to Gaines, who spoke to Winfrey by telephone yesterday, the talk show host said her own drug use had been at the behest of a man she was involved with and added that she had always been ashamed that she had "handed over my power to a man." Winfrey also said she would have felt "like a hypocrite" discussing other women's drug use while not mentioning her own, Gaines said. On the show, Gaines said, Winfrey "talked about the spiritual, about discovering God being in all of us. Everybody applauded."

Gaines said Winfrey's admission appeared to be unplanned and that after the host broke down, she asked that the taping be stopped temporarily. During the break Executive Producer Dianne Hudson came onto the set and talked quietly with Winfrey about what had happened.

Davis said the audience was "shocked. There was this big gasp." Gaines, however, said she thought the audience was more excited about shaking hands with Winfrey after the show, a ritual at "Oprah Winfrey Show" tapings, than shocked by her revelation. "It wasn't the buzz, buzz, buzz," Gaines said.

The program can be seen today in Washington at 4 p.m. on Channel 7.

Winfrey's show, which has been nationally syndicated since 1986, always has a very personal tone. It was on the program that she told of having been raped at age 9 by a cousin and then molested by others close to the family until she was 14.

She has often talked about her problems with weight, one time dragging a red wagon filled with 67 pounds of animal fat into the studio to demonstrate how much she had lost.

Winfrey began her television career in Baltimore in 1976 as a reporter and anchor, going on the next year to cohost the station's local morning talk show. Later came a move to Chicago to do a local talk show. It was an immediate hit, rivaling Phil Donahue's long-running show. Two years later it went into national syndication, and Winfrey became an almost instant sensation.

While the program continues to lead the daytime talk show ratings, its numbers have declined in the past two years while newer shows are on the upswing. Ricki Lake, with her focus on a younger audience, now stands second in popularity to Winfrey and is viewed as a serious threat to her primacy. Forbes magazine has rated Winfrey as the highest-paid entertainer in America; she owns her own production company, her own studio and the rights to her show.

Wednesday's revelation was evidence of how long her journey has been. Davis, who says her own struggle with drugs began when she was 13, said that while Winfrey's admission was difficult, she saw it as courageous, adding, "She's in a good position to help other people."

CAPTION: Winfrey says she smoked cocaine in her twenties.