Fill in the Blanks TOXICITYOnline version What to different types of lethal doses mean? by Anna Wielgopolan 1 Concentration experiment LC50 acute bigger 100 14 50% hours Lethal rats poisoning median LD stands for " Dose " . LD50 ( lethal dose ) is the amount of a substance , given all at once , which causes the death of of a group of test animals . The LD50 is one way to measure the short - term potential ( toxicity ) of substance . Toxicologists can use many kinds of animals but most often testing is done with and mice . It is usually expressed as the amount of chemical administered ( e . g . , milligrams ) per grams ( for smaller animals ) or per kilogram ( for test subjects ) of the body weight of the test animal . * * * LC stands for " Lethal " . LC values usually refer to the concentration of a chemical in air but in environmental studies it can also mean the concentration of a chemical in water . According to the Organisation for Economic Cooperation and Development ) ( OECD ) Guidelines for the Testing of Chemicals , a traditional involves groups of animals exposed to a concentration ( or series of concentrations ) for a set period of time ( usually 4 ) . The animals are clinically observed for up to days . The concentrations of the chemical in air that kills 50% of the test animals during the observation period is the value .
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