The honey produced (and sometimes eaten) from the common rhododendron plant is also called “mad honey”—and for good reason.
According to the NCPC, the toxins found in the plant cause confusion in those who ingest it, along with dangerously low blood pressure and sometimes even death.
(Fun fact: The earliest case of rhododendron poisoning is said to have occurred in the first century B.C.E. when Roman troops were allegedly poisoned with its honey. The day after they were poisoned, they were so confused that they lost a battle.)