Final answer:
In The Wonderful Wizard of Oz, poppies make people sleep, sometimes forever.
Step-by-step explanation:
In The Wonderful Wizard of Oz, the effect of poppies on people is that they make them sleep. However, it is not mentioned that they cause instant death, hallucinations, or amnesia. The poppies cause a deep and lasting sleep, and in some cases, the sleep is permanent.
Learn more about Effect of poppies in The Wonderful Wizard of Oz