AMYLOID � FIBRIL DECOMPOSING AGENT, AND THERAPEUTIC OR PREVENTIVE AGENT AND THERAPEUTIC OR PREVENTIVE FOOD COMPOSITION FOR DISEASES CAUSED BY AMYLOID � FIBRIL FORMATION
An object of the present invention is to provide: an amyloid B fibril decomposing agent containing a natural product as an active ingredient; a therapeutic or preventive agent for a disease caused by amyloid B fibril formation; and a therapeutic or preventive food composition for a disease caused by amyloid B fibril formation. Provided are: an amyloid B fibril decomposing agent containing a dry powder, ground product and/or extract of an earthworm as an active ingredient; a therapeutic or preventive agent for a disease caused by amyloid B fibril formation; and a therapeutic or preventive food composition for a disease caused by amyloid B fibril formation. The disease caused by amyloid B fibril formation is preferably Alzheimer's disease.