The Hitchhiker's Guide to the Galaxy Wiki would like to point out that it does not promote alcoholic beverages and this image is for illustrative purposes only (especially if you are Zaphod Beeblebrox).
Alcohol is a colorless volatile liquid formed by the fermentation of sugars which has an intoxicating effect on certain carbon-based life forms, according to the Encyclopedia Galactica.
The Hitchhiker's Guide to the Galaxy also mentions alcohol. It says that the best drink in existence is the Pan Galactic Gargle Blaster.
Alcohol is mentioned several times in each version of the Hitchhiker's story, usually in relation to Ford Prefect or Zaphod Beeblebrox, who consumed more alcohol than most other characters, with Ford being described as a borderline alcoholic in more than one iteration of Hitchhikers'.