Can Ghosts Drink?

[erisedstraeh2002]

No: HPFGUIDX 47498

A question that occurred to me after watching the CoS movie (this is 
a canon-based question, I promise): Can ghosts drink?  We know that 
Nearly Headless Nick tells Ron and Harry that he hasn't eaten in over 
400 years in PS/SS, and all of the food at the Deathday party in CoS 
is rotten so that the ghosts can smell it as they pass through.  But 
they can't *eat* it.  So can they drink?  Because wouldn't Nearly 
Headless Nick have had to drink the Mandrake draught in order to be 
un-petrified?

It seems to me that if ghosts can't eat, they shouldn't be able to 
drink, either.  But then how was Nearly Headless Nick restored?

~Phyllis