Background: Indian Costus extract used as traditional herbal therapy for various diseases. Ingestion of thermally oxidized palm oil causes oxidative stress leading to multiple health problems such as hypertension, dyslipidemia, atherosclerosis, as well as kidneys and liver abnormality. Aim: To investigate the toxic effects of thermally oxidized palm oil on the liver, kidneys, heart and lung of Albino rats and to evaluate the role of Indian costus in improving these effects. Methods: Forty adult healthy male albino rats equally assigned into four groups and gavaged by a single daily dose for 45 days as follows group I (control group) gavaged by distilled water, group II gavaged by 80 mg/kg of Indian costus extract, group III gavaged by one-tenth LD50 of thermally oxidized palm oil (LD50 equal 18 gm/kg) and group IV gavaged as group III in addition to 80 mg/kg of Indian costus extract. Serum was collected for biochemical analyses for liver, kidney function tests, lipid profile, malondialdehyd (MDA) and total antioxidant capacity. Also, histological examination for livers, kidneys, heart and lung from sacrificed rats of all groups were performed. Results: A significant increase in total cholesterol, triacylglycerol, low-density lipoprotein, alanine aminotransferase and aspartate aminotransferase in group III compared to group I but group IV had significantly lower levels of theses parameters than group III. The highest levels of MDA were in group III followed by group IV and the lowest levels were in group II. There was significant lower mean level of MDA in group IV than group III (7.31±0.60 vs 8.25±1.01; respectively). There were significant higher prevalence of steatosis, congestion and hepatitis in the liver of group III than group IV (p=0.004, 0.014 and 0.012; respectively). Also, there was a significant higher prevalence of atheroma in the heart, moderate and severe interstitial inflammation and granuloma around cholesterol crystal in the lung, cloudy swelling and congestion in the kidneys of group III than group IV. Conclusion: Thermally oxidized palm oil had a deleterious effect on liver, kidney, lung and heart ultrastructure, induces hyperlipidemia and oxidative stress. The extract of Indian costus had a potential protective effect against these effects.