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  1. Allan Felsot

Published Online: 15 APR 2003

DOI: 10.1002/047126363X.agr322

Encyclopedia of Agrochemicals

Encyclopedia of Agrochemicals

How to Cite

Felsot, A. 2003. LD50. Encyclopedia of Agrochemicals. .

Author Information

  1. Washington State University Tri-Cities, Richland, Washington

Publication History

  1. Published Online: 15 APR 2003


LD50 (or median lethal dose) is a statistically derived estimate of a single dose of a substance that can be expected to cause death in 50% of animals when administered by the oral route or when applied directly to the skin (dermal route). LD50 is useful for determining hazards of pesticides resulting from short-term exposure by either oral, dermal, or inhalational routes. The Environmental Protection Agency has somewhat arbitrarily ranked the oral, dermal, and inhalational LD50 values into four toxicity categories that define labeling of pesticide products.


  • LD50;
  • median lethal dose;
  • Environmental Protection Agency;
  • dermal route;
  • inhalational route;
  • oral route