In my opinion the use of the hookah in the story was more or less a metaphor. In the late 1800s the use (and perception of) opium was much different than that today, and therefore I think it was a metaphor for the dreamlike hallucinogenic events happening to her. It was as though it was meant to be an explanation for the events shifting and changing in such an erratic way. Not in the meaning of that Alice was on opium, but that the reality she was experiencing was something of a resemblance to her mind being clouded and confused by narcotics. Another event I believe to be a drug reference was the eating of the mushroom. In my opinion this was a metaphor to the idealism that further distortion of reality could perhaps bring true reality further into perspective. This ideal stemmed originally from the drinking of the “drink me” bottle, where Alice realized that the reality (or perception there of) she was living could be changed from products that she ingested.