December 2000 News

OECD Will Phase Out LD50 Test

December 29, 2000

The Organization for Economic Cooperation and Development (OECD) has agreed to abolish the LD50, a test that has been widely criticized for using large numbers of animals and causing extensive suffering.

The OECD, an international trade group that consists of representatives from 29 industrialized countries, including the United States, plans to delete the LD50 (known as Test Guideline 401) from its official manual of Test Guidelines. This manual sets guidelines for the testing of chemicals and chemical products worldwide.

The LD50 test is used to determine the potential toxicity of a chemical by estimating the dosage needed to kill 50% of a group of rats or other test animals. LD50 stands for "lethal dose 50 percent."

The LD50 will be phased out over a one-year period, and three new tests will be phased in to replace it. These alternative test methods will significantly reduce the number of animals used and, in some cases, will lessen the pain and distress associated with the test. After the phasing-out period, slated to begin in July 2001, the regulatory community no longer will accept the LD50 test.

For more information see the OECD web site here.