Demonstration: LD50

What you need and how to do the LD50 demonstration, including a list of supplies, purpose, and the procedures.
Demonstration: LD50 - Articles



  • M&M's - These represent the concentrated active ingredient of a product the company wants to bring to the market
  • "Dixie" cups - These will hold the amount of "product/M&M's" that will represent the "lethal" dose for each of you "laboratory rats/Master Gardener participants"


The purpose of this demonstration is to illustrate how the level of toxicity is
determined for a pesticide. Toxicity of pesticides is determined by the dose of the concentrated active ingredient that it takes to reach a 50% mortality rate with a test population of animals. As the Lethal Dose it takes to reach a 50% mortality rate it is expressed as the LD50 value of the chemical.


It doesn't matter how many participants that you have for this demonstration, as long as you have an even number.

Step One:

  • Fill half of the cups ½, ¾ or completely full with M&M's
  • Fill half of the cups with anywhere from 1 - 8 M& M's per cup, at least one cup should have 8 M&M's.

Step Two:

Distribute the cups those participating in the demonstration, and have the participants stand.

Step Three:

Explain to the participants that they are the test population of "laboratory rats" for the experiment that will determine the toxicity of this "product" that is heading to the market. The only thing stopping from eating as much of the "product" that they want is that the level in their cup represents a fatal dose to them as a "laboratory rat".

Step Four:

Explain to the participants that they should eat their M&M's one at a time, but fairly quickly. When they have finished eating the M&M's in their cup they should sit down because they have reached the dose that was lethal to them. When the half of the "Laboratory Rats" (those that had the smaller amounts in their cups) are seated - the LD50 value has been reached.