Calculation of LD50 values from the method of Miller and Tainter, 1944.

Dear Editor, Acute toxicity of a drug can be determined by the calculation of LD50, i.e., the dose that will kill 50% of animals of a particular species. Recently, we reported the LD50 of thymoquinone, an active principle of Nigella sativa, in mice and rats by the method described by Miller and Tainter, 1944. Since then some post-graduate students and investigators have asked us to explain the details of calculation of LD50 by this method, as the original article, being very old, is not easily available in the literature. We also faced problem in the calculations, however, we found some details for the calculation of LD50 in the Fundamentals of Experimental Pharmacology by Ghosh, which also is not easy to obtain in many parts of the world. Therefore, few lines are written, on behalf of the other authors, to elaborate the calculation of LD50 by the method of Miller and Tainter for the benefit of young researchers.