This present investigation reviews the evidence for protective effects of green tea extract (60 mg / animal / day) dietary supplements against an organophosphorus insecticide fenitrothion (Fn) toxicity in male albino rats for five weeks and describes the proposed possible biochemical and histopathological alters in blood and thyroid gland samples. Rats were divided into 6 groups. The 1st group served as a control, 2nd and 3rd groups were treated with high (FnH) and low (FnL) dose as 20 and 10 mg Fn / kg b. w, respectively, 4th group (+ve control) received green tea extract (GT), and 5th and 6th group administrated high (GTFnH) and low dose (GTFnL) with green tea, respectively. The results revealed that a reduction in plasma glucose level post intoxication with FnL compared with FnH and slight improvement induced by green tea supplementations were observed. Compared with the control group, a significant increase was observed at both fenitrothion doses in total cholesterol and thyroxine (T4) levels. Green tea supplementation counteracts the elevation of plasma total protein, and triglycerides induced as a result of fenitrothion intoxication. Prolonged supplementation of green tea extract (GTFn) declares significant improvement in induced significant reduction in hormonal plasma triiodothyronine (T3) and thyroxine (T4) concentration. Intoxication with both doses of fenitrothion (Fn) induced an increase in protein bands to be 12 bands versus (11 bands) compared with presence green tea and 3 new bands. On the other hand, Supplementation with green tea extract caused a reduction in the protein band number to be 11 bands versus 13 in the control group with 3 new protein bands. According to the histopathological alters, both treatments (Fn groups) showed thyroid follicle congestion with areas of hemorrhage and rupture of some follicles. Meanwhile, supplementation with green tea extract showed an improvement in the intoxicated thyroid tissues.