Persistence and biochemical characteristics of cypertnethrin and permethrin in the blood of male rats were studied following oral administration of a single dose containing 10 mg.kg -1 Canister Filter Replacement Parts of body weight of each pyrethroid.The highest residue concentrations of cypermethrin (2.38 ug.
ml-1) and permethrin (8.83 ug.ml-1) in rat blood tissue were detected 24 h after treatment.After two weeks cypermethrin residues decreased to 0.
013 ug.ml -1 , whereas permethrin was not detected.Both Boys Hooded Flannel pyrcthroids decreased the red blood cell (RBC) count, and packed cell volume (PCV) The greatest reduction in RBC count and PCV occurred at 504 h and 336 h respectively.Moreover, the result of post treatment white blood cell (WBC) count was influenced more by permethrin than by cypermethrin, especially after 80 h, 168 h and 504 h of treatment.
However, the blood haemoglobin concentration in treated rats was not affected by either pyrethroid.