Curcumin, an organic substance mainly derived from the plant Curcuma longa. It was reported for various biological activities and indispensable for its role on pharmacotherapeutics. However, the toxic effect of such naturally occurring compounds has been reported to be harmful after certain threshold concentration. The present study focused on the curcumin toxicity on zebrafish (Danio rerio) embryo. The lethal dosage of curcumin on zebrafish embryo was found to be 135µg/ml. The endogenous antioxidants were drastically decreased in zebrafish with different concentration. The morphological changes such as delayed hatching, spinal curvature, pericardial edema were observed.