During my intern year, my co-intern Sam had a chest pain patient who was a young female. In the review of system, she admitted she was taking some weight loss pills she ordered online from Brazil. Obviously a really reputable source.
Sam suspected that the pills contained amphetamines, but he couldn't convince the toxicology lab to analyze pills. So he took one of the capsules, broke it open and dissolved it in water. He then handed the specimen to a nurse and said, "This is urine. I want a tox screen."
The lab analyzed it and it came back positive for methamphetamines.