Aloe-emodin, a natural product isolated and purified from the root of Rheum palmatum L. with a specific in vitro and in vivo anti-neuroectodermal tumor activity, reduces the toxicity and ROS induced by both monomeric and oligomeric Aβ species, appears to have some protective effect not only against hepatocyte death but also on the inflammatory response subsequent to lipid peroxidation and has a strong non-carcinogenic stimulant-laxative action when applied to the skin, although it may increase the carcinogenicity of some kind of radiation. Aloe-Emodine dose-dependently inhibited cleavage activity of the 3CLpro with IC50 value of 366μM in the cell-based assay.