If there's anything I hate, it's washing my hair and then being with people who smoke. Yecchh ! -- Brooke Shields

Brooke Shields faced the cameras crowds and autograph seekers yesterday -- nothing unusual for the highly sought-after 16-year-old model and actress, except that the scene was a hearing room in the Rayburn Office Building and Shields was testifying before a House subcommittee.

"I haven't seen crowds like this for a hearing since Watergate," said one committee staffer who did not want her name used. "Not even Kissinger drew like this."

The committee wanted to know why the Department of Health and Human Services had dropped its slick anti-smoking advertising campaign featuring the winsome pout and heavy brow of the young Hollywood sex symbol with cigarettes sticking out of her ears. The department had spent $68,000 to produce the campaign -- including fashion photographer Francesco Scavullo's $10,000 fee -- and then suddenly decided the ads were "ineffective." David Newell III, the department's chief of staff, claimed the ads were canceled because they "used an untested, slick, Hollywood-oriented fashion merchandising concept to deal with a serious public health problem."

Shields criticized the decision and expressed her concern about cigarette smoking.

"Both of my grandfathers died because of smoking and my father smokes quite a bit," she said. "Unlike roles where I portray others under the instructions of directors, doing the smoking commercials was not really portraying a role. That was me saying it. I don't smoke and I never have except once when I had one cigarette when I was 9. I hated it. I told my mother immediately and felt ashamed and sick.

"Smoking can kill you," said Shields. "And if you've been killed you've lost a very important part of your life."

Teri Shields, Brooke's mother and manager, also testified. "A spokesperson for HHS was quoted as saying that Brooke was not 'the best' or an 'effective' person to pass the anti-smoking message across to teen-agers . . . of course, I am in a position to say that Brooke is the best candidate."

Rep. Doug Walgren (D-Pa.) said he believed the ads were canceled because the Reagan administration was bowing to pressure from the tobacco industry. "It's a matter of dollars and cents," said Walgren.

Rep. Don Ritter (R-Pa.) suggested that perhaps Shields' role as a child prostitute in the film "Pretty Baby" made her an inappropriate model for teen-agers. Shields disagreed, saying that many young fans write to her and ask her advice on personal problems.

Most of the members of the subcommittee, though, were in a decidedly uncontentious mood and seemed to enjoy the quasi-Hollywood atmosphere. Rep. Bob Whittaker (R-Kan.) held up a photograph of Shields and said, "My son has threatened to curtail his lawn-mowing activities for me this summer unless I get your autograph."

After Shields finished her testimony, photographers and fans surrounded her for pictures, autographs and a glimpse. Chairman John Dingell (D-Mich.) sounded his gavel, but it was pointless. "The chair craves the attention of the. . ." No one listened.

Rob D'Lugo, 9, gave his analysis of Shields' latest performance: "She convinced me that smoking is bad for you. When I get around 18 years old, I'm not gonna smoke even if my friends do."