``Morning-after'' birth control pills are safe and effective, the Food and Drug Administration said Monday.

``The best-kept contraceptive secret is no longer a secret,'' says FDA Commissioner David Kessler.

In a notice to be published today, the FDA says high doses of six common brands of birth control pills will prevent 75% of pregnancies if taken within 72 hours after sex. The notice includes exact doses -- information drug companies have refused to put on labels, citing legal and political fears.