Research Methods in Life Sciences Commons^™

Ld50: A Cruel Waste Of Animals

Close Up Reports

Imagine a test in which up to 100 animals are forced to consume a toxic substance in an amount high enough to kill half of them. Then imagine that the explicit purpose of the test is to kill those animals. Incredibly, such a test not only exists but each year also claims the lives of from two to four million animals.

The test is the lethal dose 50, or LD50 as it's commonly called. Its purpose is to measure the toxicity of a substance by determining how much of that substance will kill half of a group of some 60-100 …

The Ld50-The Beginning Of The End, Andrew N. Rowan

International Journal for the Study of Animal Problems

It has long been recognized that the LD50 measure (usually conducted using rats or mice) provides only a rough estimate of the acute toxicity of a chemical in humans. The Association of British Pharmaceutical Industry and the UK Chemical Industries Association have spoken out against the production of precise estimates of LD50 in rodents. However, the UK Home Office Report on the LD50 recommended that the LD50 should be allowed to continue. But scientific support for the test, as exemplified by recent papers in academic journals, has eroded significantly in the last few years.

The Ld50--The Beginning Of The End, Andrew N. Rowan

Experimentation Collection

Measurement is very important in science. Early lessons in the science classroom involve teaching students to measure lengths, volumes, weights, specific gravities and anything else within the mental and economic compass of the teacher. At the same time, the question of significance is drummed into the students' heads. Thus, if one has a meter-rule which is subdivided into centimeters (but not millimeters), one is taught that the measurement of its length to one decimal point (for example, 10.3 em) is acceptable, but that the addition of any more figures (for example, 10.325 em) is mere braggadocio. The eye can only …