What is the Hunter S. Thompson hangover cure? Playboy published a series of old letters between the "Fear and Loathing in Las Vegas" author and Playboy editor John Grabree between 1967 and 1973, and one of these letters reveals the answer, albeit unwittingly.
The note, which is scrawled on Beverly Hills Hotel stationery, reads, "P.S. -- inre: Oui's request for 'my hangover cure' -- it's 12 amyl nitrites (one box), in conjunction with as many beers as necessary. OK H." I'll save you the Googling: amyl nitrites, also known as poppers, have been a choice drug of the club culture since the 70s.
Although the hair of the dog and drugs aren't exactly the best hangover remedies (time and hydration are), Hunter S. Thompson's hangover cure is one more unusual note to add to his annals.