WASHINGTON (AP) _ Illinois Rep. John Grotberg, who lapsed into unconsciousness six weeks ago after suffering complications from an experimental cancer treatment, has emerged from the coma and is recuperating, it was reported Tuesday.

Doctors said they are listing the condition of the 60-year-old Republican congressman as ''serious but stable,'' an improvement over the ''critical but stable'' assessment they had posted for more than five weeks.

''He is out of his coma and is showing some responsiveness,'' said Colleen Henrichsen, a spokeswoman for the National Institutes of Health in suburban Bethesda, Md.

Grotberg, a candidate for re-election, has been hospitalized at NIH since January. He had undergone a round of a newly developed cancer therapy at NIH just before falling into the coma late that month.

''At times, he will still lapse into sleep or become unresponsive, but those times are getting shorter and shorter on a daily basis,'' said Steve Trossman, Grotberg's press secretary.

Trossman quoted one the lawmaker's physicians - Dr. Alfred Chang - as saying the congressman is alert and responsive enough to be considered out of the coma.

Trossman said the congressman's wife, Jean, and other members of his family have attempted to provide mental stimulation for the lawmaker as he lingered in the coma. They have talked to Grotberg, played tape recordings of get well wishes from friends and constituents, and played the television in his room.

Grotberg, a freshman representative, has been afflicted with cancer for more than a decade. At the time he started the experimental treatment last year, the cancer had spread from his colon to his liver.

Under the new therapy, Grotberg's blood cells were being recycled through his body along with a protein compound to enhance the cells' disease-fighting ability. An artery through which he was receiving the cell and protein injections became infected and set off a chain of medical events leading to the coma.