In the present paper,we report a reproducible,cost effective,fast response method for detection of malathion and its effects on leukocytes in different human blood groups.Spectroscopic methods(UV-Vis spectrometry)and Fourier transform infrared coupled with solid phase extraction were applied for analyzing malathion content in human blood plasma.The spiking levels of malathion in the range of 0.1-1.7μg/mL were extracted from blood plasma samples using SPE.The present active functional groups(C=0;P-O-C;-OH;P=S)were also characterized.The recovery rate of malathion was 80%±4.5%.The calculated correlation coefficient was 0.9799,indicating the linearity of the results.The limit of detection(LOD)and limit of quantification(LOQ)were(0.1-1.7)μg/mL and(0.3-1.5)μg/mL,respectively.Malathion<1.0μg/mL showed no significant change while higher levels of malathion exposure(1.5μg/mL and 3.0|ig/mL)reduced the number of white blood cells.In conclusion,the spectroscopic results may be useful to understand the mechanism of other pesticides such as methyl parathion and parathion. In the present paper, we report a reproducible, cost effective, fast response method for detection of malathion and its effects on leukocytes in different human blood groups. Spectroscopic methods (UV-Vis spectrometry) and Fourier transform infrared coupled with solid phase extraction were applied for analyzing malathion content in human blood plasma. The spiking levels of malathion in the range of 0.1-1.7 μg / mL were extracted from blood plasma samples using SPE. present present active functional groups (C = 0; POC; -OH; P = S) was also characterized. The recovery rate of malathion was 80% ± 4.5%. The calculated correlation coefficient was 0.9799, indicating the linearity of the results. Limit of detection (LOD) and limit of quantification (LOQ) were (0.1- 1.7 μg / mL and 0.3-1.5 μg / mL respectively. Malathion <1.0 μg / mL showed no significant change while higher levels of malathion exposure (1.5 μg / mL and 3.0 | ig / mL) reduced the number of white blood cells.In conclusion, the spectroscopic results may be useful to und erstand the mechanism of other pesticides such as methyl parathion and parathion.