The Senate acted late yesterday to curb the worst excesses of magazine sales sweepstakes and other direct-mail promotional games that prey on the gullible and the elderly. The bill passed by a vote of 90 to 0.

The legislation would require sweepstakes mailers to note clearly and prominently in their solicitations that no purchase is necessary to enter a contest and that a purchase will not enhance the chances of winning a prize.

And the U.S. Postal Service, which now is legally limited in its efforts to police misleading and deceptive solicitations, would be given subpoena power to investigate alleged abuses. Civil fines for violations could run as high as $2 million, depending on the number of mailings involved.

Sweepstakes promoters also would be obligated to spell out all the terms and conditions of their promotion, provide their principal place of business or another address where they can be contacted, and clearly reveal the estimated odds of winning each prize, said Sen. Susan Collins (R-Maine), the bill's chief sponsor.

Because of the Senate's support for the bill, the sweepstakes industry's lobbyists are expected to try to sidetrack it in the House, according to one Republican aide. The bill's fate is dependent on whether the House GOP leadership pushes it, observers said.