Lum was a cheap Corellian liquor that produced a mild buzz, but was unable to produce extreme intoxication in Humans and most other common sentient species. Overindulgence was required to feel the intoxicating effects, and overdose and poisoning were impossible. It was the synthehol of the Star Wars universe.
In very extreme cases, lum-aholics have been known to hallucinate about a green-haired girl in a leopard-skin bikini.
Those seeking to get blasted out of their skulls would be better off indulging in Pan Galactic Gargle Blasters or 40s of Samuel Jackson Beer.