Objective A program was developed to calculate the median lethal dose(LD50) with Bliss algorithm. Methods The program was built in R,and its results were compared with previous calculations in publications. Results The legibility and ease of understanding of the program were much greater,and the accuracy of results was also presented. Conclusions It is an effective way for LD50 calculations performed by Bliss and such related issues in toxicology and pharmacology via developing in R.