An official website of the United States government.

We've made some changes to EPA.gov. If the information you are looking for is not here, you may be able to find it on the EPA Web Archive or the January 19, 2017 Web Snapshot.

Acute Oral Toxicity Up-And-Down-Procedure

The files listed below include the program and associated documentation for conducting the Up-and-Down Procedure, an alternative acute toxicity test that provides a way to determine the toxicity of chemicals with fewer test animals by using sequential dosing steps.

The up-and-down method is used in the Series 870 Health Effects Test Guidelines for acute toxicity testing and by the Organisation for Economic Co-operation and Development member nations. It replaces the traditional acute oral toxicity test formerly used to characterize industrial chemicals, pesticides, and their mixtures.

This method maintains the performance of acute testing for applications that use the median lethal dose (classic LD50) test while achieving significant reductions in animal use. It uses sequential dosing, together with sophisticated computer-assisted computational methods during the execution and calculation phases of the test.

The AOT425StatPgm program to perform calculations required to implement the OECD Acute Oral Toxicity Test Guideline 425 procedure (OECD TG 425). The program calculates:

  • the doses for the test animals;
  • when to stop dosing animals; 
  • the specified LD50; and
  • a confidence interval for the LD50.

This is a self-extracting zip file that will install the program on your computer in two steps.

Note: This is to confirm that use of the computer program, AOT425StatPgm, developed by Westat for EPA, is freely given, and there are no licensing restrictions in connection with its use. The user is cautioned to read the User Documentation regarding any limitations and applicability and hardware requirements.

OPPTS Harmonized Test Guideline 870.1100 Acute Oral Toxicity

You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.