Bezoar

bezoar stone were sought because they were believed to have the power of a universal antidote against any poison. It was believed that a drinking glass which contained a bezoar would neutralize any poison poured into it. The word "bezoar" comes from the persian pâdzahr (پادزهر), which literally means "protection from poison."
In 1575, the surgeon ambroise paré described an experiment to test the properties of the bezoar stone. At the time, the bezoar stone was deemed to be able to cure the effects of any poison, but paré believed this was impossible. It happened that a cook at paré's court was caught stealing fine silver cutlery. In his shame, the cook agreed to be poisoned. He then used the bezoar stone to no great avail as he died in agony seven hours later.[5] paré had proved that the bezoar stone could not cure all poisons as was commonly believed at the time.
A famous case in the common law of england (chandelor v lopus, 79 eng rep. 3, cro. Jac. 4, eng. Ct. Exch. 1603) announced the rule of caveat emptor, "let the buyer beware" if the goods he purchased are in fact genuine and effective. The case concerned a purchaser who sued for the return of the purchase price of an allegedly fraudulent bezoar. (how the plaintiff discovered that the bezoar did not work is not discussed in the report.) Judicial scepticism over the alleged magical powers of bezoars may well have justified this judgment in this particular case. The ruling, however, was seized on and formed an impediment to the formation of effective consumer protection remedies and the law of implied warranty well into the nineteenth century.
The merck manual of diagnosis and therapy notes that consumption of unripened persimmons have been identified as causing epidemics of intestinal bezoar stone, and that up to ninety percent of food boluses that occur from eating too much of the fruit require surgery for remova

Http://en.wikipedia.org