Introduction: Ectomethrin (ECM) a synthetic pyrethroid, has broad spectrum use in agriculture, domestic and veterinary medical applications. Its prolonged and indiscriminate use has both acute and chronic toxicity in non-target species including humans.   Aim of the work: To evaluate the toxic effects of ectomethrin (ECM) inhalation in rats, and its recovery after stopping treatment.  Materials and Methods: A total of forty Wistar male albino rats were divided into four groups. First group served as control group and received no treatment. Second group; ECM45 was administered a daily dose of 0.3 ml/kg/day by inhalation for 45 days. Third group; ECM90 group was administered the same ECM dose for 90 days. The forth group is the recovery group; Rec30 was administered the same dose of ECM by inhalation for 90 days, then the inhalation was stopped and the animals were left to recover without any treatment for another 30 days. At the end of the experiment, blood and tissue samples were obtained.  Results: ECM-intoxication revealed significant alterations in the oxidative stress parameters, malondialdehyde and superoxide dismutase in all treated groups. However, these alterations were attenuated in the recovery group and tended to approach normal levels. Histopathologically, ECM-intoxication revealed dramatic changes in liver and lung tissues and induced minor changes in the heart. The liver showed ballooning degeneration, focal lymphocytic aggregation, pyknotic nuclei, dilated central vein, collapsed sinusoidal spaces, focal necrosis and vascular degeneration. The lung revealed marked respiratory inflammation and focal necrosis and the heart showed myocardial hypertrophy. The recovery group had less severe complications in investigated tissues.
Conclusion: ECM inhalation resulted in severe biochemical and histological alterations that were attenuated after stopping inhalation.