The objective of the present work was to elucidate the peculiarities of isolation of 4-nitroanilin from the biological material with the use of TLC and HPLC techniques, low-pressure column chromatography, and spectrophotometry. The results of the study made it possible to substantiate the application of 1,4-dioxane as an agent for the isolation of 4-nitroanilin from the biological material. The optimal conditions of the procedure for isolation of 4-nitroanilin from the hepatic tissue using 1,4-dioxanewere determined. It was shown that the 4-nitroanilin thus obtained can be purified from the co-extracted substances on a L 40/100 mcm silicagel column. The quantitative assessment of the isolation of different amounts of 4-nitroanilin from the cadaveric liver is proposed taking into consideration the extraction conditions.