A blond-haired doll that soils disposable diapers with pink liquid and then develops diaper rash was judged the worst toy of the Christmas season by a consumer group yesterday.

The eight-inch doll, known as "Baby Wet-N-Care" and manufactured by Kenner Toys, is fed a solution of water mixed with two orange tablets. The doll comes with a solution to remove the rash, but a box of replacement diapers costs $3.15.

The group that judged this season's toys, the Consumer Affairs Committee of Americans for Democratic Action, evaluated 60 types of toys in 30 metropolitan area stores. The group also conducted a survey of toy prices in stores, finding that G.C. Murphy's at 12th and G streets NW had the highest prices of the metropolitan area and that Tunz-A-Fun in Alexandria had the lowest.

The group used five criteria to separate the "best" from the "worst": toys should not hurt the child, should be appropriate for the age group specified on the box, should not bore the child, should not break easily and should live up to claims made in TV advertisements.

Ann Brown, spokesman for the group, said "Baby Wet-N-Care" was faulted because the orange tablets that come with the doll introduce children to pill popping, because children need the guidance of an adult to mix the ingredients properly and because television commercials lead children to believe that the doll develops "pretty pink pimples when in fact it makes quite a big mess."

"And, I can't figure out the value of cleaning up diapers," Brown said.

No one connected with Kenner Toys, a Cincinnati firm, could be reached for comment.

"Alvin the Aardvark," a 15-inch long stuffed anteater that comes with two foam rubber ants, also received low marks from the group. Alvin is a pulltoy who picks up ants with his nose. On television, Brown said, it appears that Alvin casts away ants in addition to picking them up.

"But the Alvins we have won't toss the ant -- they're just regular anteaters who keep them," said Brown. "That's no fun -- that's not a game. Pretty soon the kid uses Alvin as a push toy and that's not what you bought him for."

The group, which also surveyed toy prices in the District and suburban stores, said it had rated G.C. Murphy's at 12th and G streets NW as the most expensive store for toys in the metropolitan area.

The assistant manager of the Murphy's store said last night he could not comment, and that no higher company official could be reached.

Tunz-a-Fun in Alexandria was rated as the store in the area with the least expensive toy prices.Its prices were 3 percent lower than those of Toys-R-Us in Rockville, which had the lowest prices during last year's survey.

Four members of the consumer group checked prices in about 30 stores Nov. 14-25.

Downtown Woodward/Lathrop's prices were almost as expensive as Murphy's and were about 2 percent higher than Bloomingdale's at the White Flint Mall in Bethesda, it was found.

In the District, Bargaintown, Hecht's and Sears were found to have the least expensive toys. In the suburbs, Woolco in Rockville and K-Mart in Landover had some of the lowest toy prices, in addition to Tunz-A-Fun and Toys-R-Us, the group reported.

The group found that Korvette's in Rockville "has emerged as one of the highest priced stores to shop for toys in the entire (suburban) area."