"When bees feed on the pollen of rhododendron flowers, the resulting honey can pack a hallucinogenic punch." Source: Atlas Obscura.
"It’s called mad honey, and it has a slightly bitter taste and a reddish color. More notably, a few types of rhododendrons ... contain grayanotoxin, which can cause dramatic physiological reactions in humans and animals. Depending on how much a person consumes, reactions can range from hallucinations and a slower heartbeat to temporary paralysis and unconsciousness."
"The intoxicating effects of mad honey have been known for thousands of years. Not surprisingly, there have been many famous episodes of human inebriation caused by its consumption. Xenophon, Aristotle, Strabo, Pliny the Elder and Columella all document the results of eating this 'maddening' honey, believed to be from the pollen and nectar of Rhododendron luteum and Rhododendron ponticum. According to Xenophon, an invading Greek army was accidentally poisoned by harvesting and eating the local Asia Minor honey, but they all made a quick recovery with no fatalities. Having heard of this incident, and realizing that foreign invaders would be ignorant of the dangers of the local honey, King Mithridates later used the honey as a deliberate poison when Pompey's army attacked the Heptakometes [1] in Asia Minor in 69 BCE. The Roman soldiers became delirious and nauseated after being tricked into eating the toxic honey, at which point Mithridates's army attacked." Source: Wikipedia.
[1] "In about 65 BCE, Pompey's army was approaching Colchis. Mithridates' allies there, the Heptakometes, were described by Strabo as 'utterly savage' mountain barbarians, dwelling in tree forts and living on 'the flesh of wild animals and nuts.' The tribe was feared for attacking wayfarers - suddenly leaping down on them like leopards from their tree houses. The Heptakometes may have received specific orders from Mithridates on how to ambush the Roman army. What we do know for a fact is that they gathered up great numbers of wild honeycombs dripping with toxic honey and placed them all along Pompey's route. The Roman soldiers stopped to enjoy the sweets and immediately lost their senses. Reeling and babbling, the men collapsed with vomiting and diarrhea and lay on the ground unable to move. The Heptakometes easily wiped out about one thousand of Pompey's men." - Greek Fire, Poison Arrows, and Scorpion Bombs: Biological and Chemical Warfare in the Ancient World by Adrienne Mayor. (Quoted in Roman Times)
Taking mad honey sounds like a dangerous way to get loaded. According to the Drug Classroom, "[t]he core symptoms of mad honey poisoning include nausea, vomiting, salivation, headache, blurred vision, sweating, weakness, circumoral paresthesia, tongue numbing, fainting, drowsiness, drunkenness, tingling, and seizures." The toxins in the honey can also cause "1st to 3rd degree heart block, asystole, and myocardial infarction."