Early in September, Oxfam, the British humanitarian organization, was circulating a petition calling on the United States to "put health before wealth" by supporting relaxation of international patent policies that Oxfam says make vital medicines too expensive for developing countries. But immediately after the terrorist attacks at the World Trade Center and the Pentagon, the petition was removed from Oxfam's Web site. When it returned last week, the cartoon drawing of Uncle Sam had been replaced with a picture of a bottle of pills, and the language singling out the United States had been muted. The group also canceled a news conference at which it had planned to denounce the United States for its patent stance.

"It was not appropriate given the kind of national trauma that was occurring here," said Severina Rivera, a senior policy adviser at Oxfam America in Washington. Since the terrorist attacks, many other advocacy groups have been canceling planned actions as well, or have toned down oratory that could be perceived as insensitive or even unpatriotic. The Sierra Club has removed the "W Watch" column from its Web site because it could be perceived as critical of President Bush. It has also stopped its phone solicitations and pulled advertising from the air. The A.F.L.-C.I.O., the Mobilization for Global Justice and many other groups canceled plans to protest at the annual meetings of the World Bank and International Monetary Fund. The bank and fund later canceled their meetings, which were scheduled for the end of this month in Washington. Friends of the Earth let the one-year anniversary of its discovery of unauthorized genetically modified corn in the food supply pass without even a news release. "No one's interested in gene-altered corn right now," said Mark Helm, a spokesman for the organization. Even if activists are broadcasting their messages, few people seem to be listening. "What we find is a blackout on coverage and attention to activism," said Asia Russell, a member of Act Up Philadelphia, which has been campaigning to have lower priced drugs available to treat AIDS in Africa. Some groups fear that if they are perceived as unpatriotic it will hurt them in the long run. "We strongly need to avoid any perceptions that we are being disrespectful to President Bush," Allen Mattison, director for media relations at the Sierra Club, wrote in an internal memorandum. "Now is the time for rallying together as a nation; the public will judge very harshly any groups whom they view as violating this need for unity."

But several activists say they are concerned that the self-restraint, especially as expressed in the Sierra Club memorandum, has gone too far. "This self-censorship is dangerous in itself," said Kristin Dawkins, director of the globalism program at the Institute for Agriculture and Trade Policy in Minneapolis, which is critical of the influence of multinational corporations on agriculture. "It allows some of the very, very dangerous policies that the Bush administration is pursuing this very minute to go forward unchecked."

Environmental groups say they are concerned that some proponents of opening the Arctic National Wildlife Refuge to oil drilling are pushing their cause using the prospect of energy disruptions from a possible war. Some human rights groups, while dropping their usual causes, are starting campaigns to oppose any rush toward war and steps that they perceive would erode domestic civil liberties in the name of counterterrorism. Ms. Rivera of Oxfam, a lawyer who normally deals with trade issues, has shifted abruptly to analyzing international laws regarding military responses.

"We have a position urging military restraint," she said. The International Action Center in New York had been planning a march in Washington on Saturday against the International Monetary Fund and World Bank. But with the financial meetings canceled, the group says it will now have an antiwar demonstration in Washington the same day, said Teresa Gutierrez, a national co-director. She dismissed concerns that such demonstrations would be unpopular. "We went to the vigils at Union Square with some caution and sensitivity and found there was no problem in handing out antiwar fliers," she said. Some groups are continuing with their campaigns. The Organic Consumers Association went ahead last week with planned leafleting outside Starbucks outlets to protest the use of genetically modified ingredients and to promote the sale of coffee grown by people earning what the association said was a decent wage. Ronnie Cummins, national director of the association, said about 20 of 300 volunteers nationwide postponed distributing the leaflets. Mr. Cummins said he received one irate e-mail message "from somebody who said it was a shame and why didn't we move to Afghanistan." But he added that his volunteers said that Wall Street resumed business "and so did our criticism of corporate behavior."