Onset is usually marked by extreme nausea, followed by vomiting, which may be very severe. Raw kidney beans contain from 20,000 to 70,000 hau, while fully cooked beans contain from 200 to 400 hau. The syndrome is usually caused by the ingestion of raw, soaked kidney beans, either alone or in salads or casseroles. As few as four or five raw beans can trigger symptoms. Reports of this syndrome in the United States are anecdotal and have not been formally published.
All symptoms usually resolve within several hours of onset.
Hospitalization has occasionally resulted, and intravenous fluids may have to be administered. Although of short duration, the symptoms are extremely debilitating. The difficulty in food analysis is that this syndrome is not well known in the medical community. Other possible causes must be eliminated, such as Bacillus cereus , staphylococcal food poisoning, or chemical toxicity. As previously stated, no major outbreaks have occurred in the U.S. Outbreaks in the U.K. are far more common.