Poison

A young high school male comes in to the hospital with a lethal poisoning, but neither House or the rest of his team can find out what has caused it. House decides to send Cameron and Chase to the teen's home to find the hot new drug House is sure he's taking. They don't find drugs, but do find something that would explain his symptoms. That is until another student comes in with the exact same symptoms. Meanwhile, an 82-year-old patient becomes obsessed with House who is trying to figure out the basis of her renewed fascination with her sexual feelings.