The Bush administration reversed itself Wednesday and withdrew four changes in organic food standards that critics had said threatened to undermine public trust in the word organic.

Secretary of Agriculture Ann M. Veneman announced yesterday that she was rescinding changes her department made last month to federal organic food standards.

Last month the departments Agricultural Marketing Services issued what it called clarifications of the standards, allowing antibiotics in dairy cows, certain chemicals in pesticides and livestock feed containing nonorganic fish meal. When the changes were announced they created a firestorm in the organic community.

Ms. Veneman acknowledged the reaction at a news conference yesterday.

"There has been a tremendous amount of interest in this, of concern about what it does," Ms. Veneman said. "This is an issue that has come up in the media over the past couple days" and, she added, "we are taking action to rescind what A.M.S. had done."

Critics of the changes said officials had not consulted with the National Organic Standards Board, an advisory panel of experts, as the law requires. Ms. Veneman said those officials would now work with the board to decide how to deal with the issues.

She said, though, that the marketing services had acted in good faith.

The new directives would have permitted organic dairy animals to be treated for disease with any drug, including antibiotics and growth hormones, and remain on an organic farm, as long as the producer waited 12 months to sell milk from those animals.

They would also have allowed the use of fish meal as a feed supplement for organic livestock even though fish meal can contain synthetic preservatives and contaminants like mercury and PCBs.

And they would have permitted the use of certain pesticides even if the inert ingredients of those pesticides are prohibited.

In explaining the directives, department officials had said they were not creating new rules but establishing the limits of existing regulations.

Senator Patrick J. Leahy, Democrat of Vermont and father of the National Organic Program, which set up the standards two years ago, commended Ms. Veneman for her response.

"The secretary has decided to follow the law and to consult with the National Organic Standards Board, and that is welcome news," Mr. Leahy said. "The organic standards and labeling program is still in its infancy, and this is a critical time for its credibility. This programs credibility has been built with full public and stakeholder participation, and we need to keep it that way."

The withdrawal of the directives came the same day Mr. Leahy began circulating a letter to Senate colleagues for signatures, urging the retraction of the moves.