Several herbs and herbal products have been recommended to promote a healthy thyroid regulation. Medicinal plants and natural products represent one of the most popular alternative treatments. The present study focuses the anti-thyroid activity in Moringaoleifera Lam in methimazole induced hypothyroidism in female albino rats. Moringaoleifera were collected from the surrounding area of thanjavur district, traditionally the plant is used as antispasmodic, stimulant, expectorant and diuretic. Methimazole inhibits the enzyme thyroperoxidase, which normally acts in thyroid hormone synthesis by oxidizing the anion iodine (I-) to iodine (I0), facilitating iodine’s addition to tyrosine residues on the hormone precursor thyroglobulin, a necessary step in the synthesis of triiodothyronine (T3) and thyroxine (T4). The aim of the current study was to evaluate property of anti thyroid on Siddha medicinal plant as well as natural product by using previous events.