With growing interest in using alternative and complementary medicine, especially medicinal plants, because of low cost and less adverse effects. This study was performed to evaluate the anti-hyperthyroidism effects of medicinal herb, chestnut (Castanea sativa mill) that used to enrich yoghurt with different premixes on levothyroxine (LT4)-induced hyperthyroidism rats. Male wistar rats were divided into seven groups five each, namely, normal group (-ve), hyperthyroidism control group (+ve), hyperthyroidism plus PTU as treated with standard drug, hyperthyroidism plus enriched-chestnut yoghurt prepared with chestnut by cow milk (T 1 ) , hyperthyroidism plus enriched-chestnut yoghurt prepared with chestnut by blending cow milk [1:1] (T 2 ), hyperthyroidism plus enriched-chestnut yoghurt prepared with chestnut by blending cow milk at [3:1] (T 3 ) and hyperthyroidism plus enriched-chestnut yoghurt prepared with chestnut by blending cow milk at [6:1] (T 4 ), rats in all groups except normal were injected with LT4 for 2 weeks to induce hyperthyroidism and then were administrated each treatment for 6 weeks. Biomarkers linked to hyperthyroidism were determined. Results, showed that, serum TC, TG, LDLc, VLDL-c, Urea Nitrogen, AST, ALT, Triiodothyronine and Thyroxine , meanwhile, were significantly reduced in T 3 , T 4 and PTU groups compared with the hyperthyroidism (+ve) group . Meanwhile, Serum HDL-c, uric acid, creatinine, and TSH were significantly increased in the enriched-chestnut yoghurt with different premixes and PTU groups. Results suggest that chestnut might suppress different biomarkers, Triiodothyronine, Thyroxine and TSH activities by modulating their concentrations and therefore, enriched yoghurt with chestnut could be an alternative therapy for hyperthyroidism.