Two doctors, Dean and Gable, are treating a man with lung disease. They’re explaining how his smoking weed has led to his condition worsening.
“But it’s just herbal!” the patient protested. “How can it be bad?”
Dr. Jenkins sighed. “Nature isn't all innocent. Apricot stones contain lethal amounts of cyanide. There is a certain plant in my back garden - if you sit under it for just 5 minutes, you will die. Just because it’s natural doesn’t mean it’s safe for you!”
The man seemed to accept that, and promised to stop his smoking.
After he left, the doctors went to lunch. As they were sitting down to eat, Dr. Smith asked, “Oh by the way, what IS that plant that kills you if you sit under it?”
“A water lily."