An extract of soybeans enriched in Bowman-Birk inhibitor (BBI), a soybean-derived, 71-amino acid, polypeptide and serine protease inhibitor with potential chemopreventive activity. Bowman-Birk inhibitor contains distinct inhibitory sites for trypsin and chymotrypsin. Although the exact mechanism by which BBI suppresses carcinogenesis is unknown, its antiproliferative activity appears to be linked to the chymotrypsin inhibitory region. or A partial or complete block of the small or large intestine that keeps food, liquid, gas, and stool from moving through the intestines in a normal way. Bowel obstructions may be caused by a twist in the intestines, hernias, inflammation, scar tissue from surgery, and certain types of cancer, such as cancers of the stomach, colon, and ovary. They may also be caused by conditions that affect the muscles of the intestine, such as paralysis. Signs and symptoms may include pain and swelling in the abdomen, constipation, diarrhea, vomiting, and problems passing gas. Most bowel obstructions occur in the small intestine. Also called intestinal obstruction.