This study included an attempt to isolate and purify Human Epidermal Growth Factor Receptor (EGFR) from healthy human plasma using different biochemical technique. Two peaks had been isolated by gel filtration chromatography from the precipitate produced by using ammonium sulfate. The first peak (peak A) had a high level of EGFR. Furthermore, the purity of isolated EGFR peak A had been identified by the high-performance liquid chromatography and by gel electrophoresis technique. The results obtained from high performance liquid chromatography showed that there was a good identity in retention time between the standard and the isolated EGFR peak A. The approximate molecular weight of partially purified EGFR peak A was 75318±100 and 73029±100 dalton using gel filtration chromatography and gel electrophoresis technique respectively. The effect of the isolated EGFR peak A on some histopathological aspects in adult female albino rats had been studied. The result showed that the treatment with three different concentrations of peak A causes alteration in the normal architecture of the liver and kidney characterized by infiltration of lymphocytes, coagulative necrosis, hemorrhage, increase in collagen fibers deposition, hyperplasia, pre-neoplastic lesion with bizarre nucleus, and adenoma. These irreversible pathological changes which occurred in these organs may be converted to malignance if take longer time (more than one month). According to the findings of this study, high levels of HER2 cause irreversible pathological changes in the liver and kidney, which can progress to cancer over time.