"Bed rest and perhaps a large, steaming mug of hot chocolate. I always find that cheers me up..."
-- Dumbledore, after Harry saved Ginny and defeated Tom Riddle in the Chamber of Secrets (CS18)
A Muggle treat just as appealing to Wizards.
- served at the Burrow (CS4)
- and on the Knight Bus (PA3)
- Dumbledore came down in the middle of the night for some, but found the Petrified Colin Creevey instead (CS10)
- when Ginny Weasley was sent to the hospital wing after her ordeal in the Chamber of Secrets, Dumbledore suggested that she be given a cup of hot chocolate (CS18)
Since Professor Lupin and Madam Pomfrey were convinced that chocolate had healing qualities, we can probably assume the same is true for hot chocolate. Dumbledore hints at this when prescribing hot chocolate for Harry, Ron and Ginny.