Bezoars

Quote	Source
"Let's try again. Potter, where would you look if I told you to find me a bezoar?" Hermione stretched her hand as high into the air as it would go without leaving her seat, but Harry didn't have the faintest idea what a bezoar was. ... "I don't know, sir." ... "Sit down," he snapped at Hermione. "For your information, Potter, ... A bezoar is a stone taken from the stomach of a goat and it will save you from most poisons."	Book 1, Pages 137-138 Sorcerer's Stone, Chapter 8, "The Potions Master"
He found it hard to concentrate on Snape's Potions test, and consequently forgot to add the key ingredient - a bezoar - meaning that he received bottom marks.	Book 4, Page 396 Goblet of Fire, Chapter 22, "The Unexpected Task"
...Harry bent over the Half-Blood Prince's book and turned a few pages with unnecessary force. And there it was, scrawled right across a long list of antidotes: Just shove a bezoar down their throats. Harry stared at these words for a moment. Hadn't he once, long ago, heard of bezoars? Hadn't Snape mentioned them in their first-ever Potions lession? "A stone taken from the stomach of a goat, which will protect from most poisons." ... He hastened toward the store cupboard and rummaged within it, ... until he found, at the very back, a small cardboard box on which had been scribbled the word BEZOARS. ... Inside were half a dozen shriveled brown objects, looking more like dried-up kidneys than real stones. Harry seized one, put the box back in the cupboard, and hurried back to his cauldron. ... "Oh, you're like your mother. ... Well, I can't fault you. ... A bezoar would certainly act as an antidote to all these potions!" ... "Just like his mother, she had the same intuitive grasp of potion-making, it's undoubtedly from Lily he gets it. ... Yes, Harry, yes, if you've got a bezoar to hand, of course that would do the trick ... although as they don't work on everything, and are pretty rare, it's still worth knowing how to mix antidotes. ..."	Book 5, Pages 377-378 and 397-398 Order of the Phoenix, Chapter 18, "Birthday Surprises"
"There you are then," said Slughorn handing Harry and Ron a glass of mead each before raising his own. "Well, a very happy birthday, Ralph -" "Ron -" whispered Harry. But Ron, who did not appear to be listening to the toast, had already thrown the mead into his mouth and swallowed it. ... Ron had dropped his glass; he half-rose from his chair and then crumpled, his extremities jerking uncontrollably. Foam was dribbling from his mouth, and his eyes were bulging from their sockets. ... Harry lept over a low table and sprinted toward Slughorn's open potion kit, pulling out jars and pouches, while the terrible sound of Ron's gargling breath filled the room. Then he found it - the shriveled kidney like stone Slughorn had taken from him in potions. He hurtled back to Ron's side, wrenched open his jaw, and thrust the bezoar into his mouth. Ron gave a great shudder, a rattling gasp, and his body became limp and still.
PONDER THIS
"An excellent point," said Professory Dumbledore. "My own brother, Aberforth, was prosecuted for practicing inappropriate charms on a goat."	Book 4, Page 454 Goblet of Fire, Chapter 24, "Rita Skeeter's Scoop"