A method for producing a purified Auricularia auricula Polysaccharide (AP) extract of Auricularia auricula (AA). A hydrated predetermined amount of AA is filtered and extracted, producing a first pre-extract. A plurality of additional hydrated predetermined amounts of AA is separately filtered and extracted to produce a plurality of additional pre-extracts. The pre-extracts are combined to form a first extract. The first extract is concentrated and suspended, forming a precipitate. The precipitate is purified to form a first filtrate, and repurified to form a second filtrate. The first and second filtrates are combined to form a first combined filtrate, which is concentrated, purified and dried to form a concentrated extract. The concentrated extract is purified to form a third filtrate, and repurified to form a fourth filtrate. The third and fourth filtrates are combined to obtain a second combined filtrate, which is concentrated, purified and dried to obtain the purified Auricularia auricula Polysaccharide extract of AA. A method of reducing the serum cholesterol in mammals by administering a pharmaceutically effective amount of the purified Auricularia auricula Polysaccharide (AP) extract of Auricularia auricula (AA) produced according to the foregoing method.