Supposedly, doctors sometimes advise patients to drink something (wine, carrot juice, lemonade or something else) after taking a hot bath. A popular joke was first published in The Humorist (London) in 1929:
   
Friend: “Well, did you follow my advice and drink a stiff whisky after a hot bath?”
Invalid: “I did my best, old chap, but I couldn’t finish drinking the hot bath.”
   
   
10 April 1929, Brooklyn (NY) Daily Eagle, “The Jest Column,” pg. A1, col. 6:
A LONG DRAUGHT.
Friend: “Well, did you follow my advice and drink a stiff whisky after a hot bath?”
Invalid: “I did my best, old chap, but I couldn’t finish drinking the hot bath.”
—The Humorist, London.
 
22 November 1931, Sunday American-Statesman (Austin, TX), “College Humor,” pg. 9, co. 6:
“Did you follow my advice and drink a hot lemonade after a hot bath?”
“I did my best, pal, but I couldn’t finish drinking the hot bath.”
—Idaho Blue Bucket
 
9 August 1959, Chicago (IL) Sunday Tribune, “Charley Weaver’s Letters from Mamma” by Cliff Arquette, TV sec., pg. N10, col. 1:
Grandma Ogg had to go to the doctor and he told her to drink a glass of huckleberry wine after a hot bath. However, she never go to the wine—she couldn’t finish drinking the hot bath.
 
9 October 1967, Austin (TX) Statesman, “Tell Me Why!” by A. Leokum, pg. 26, col. 5:
Doctor: Did you drink the carrot juice after the hot bath?
Patient: I haven’t finished drinking the hot bath yet.
 
August 2004, Boys’ Life, “Think & Grin,” pg. 53, col. 3:
Patrick: The doctor told me to drink carrot juice after a hot bath.
Ariana: Did it help?
Patrick: I don’t know. I can never finish drinking the hot bath!
Patrick Porter, Warren, Minn.
   
Google Books
The Mammoth Book of Irish Humour
By Aubrey Malone
London: Constable & Robinson Ltd
2012
Pg. ?:
I wasn’t feeling myself so I went to the doctor. He told me to take a glass of hot milk after a bath. That was three weeks ago. I’m still drinking the hot bath.
Letter quoted by Jimmy Cricket
 
Twitter
Mark Summers
‏@markysumm
My doctor recommends I drink a glass of wine after a hot bath. I think I will skip the wine, I’m struggling to drink all my bath as it is…
8:18 AM - 28 May 2012
 
Twitter
Mina
‏@Darkwal96
My doctor told me to drink a glass of wine after a hot bath, but I couldn’t even finish drinking the hot bath!
A quick bad joke #badjoker
6:16 PM - 27 Oct 2013
 
Twitter
Just Like That!
‏@TheTCooperShow
Doctor said “drink a glass of wine after a hot bath.“But I can’t finish drinking the hot bath! #TommyCooperQuotes
3:22 AM - 30 May 2015
 
Twitter
Crap Jokes
‏@TheCrapJoker
My doctor told me to drink a glass of wine after a hot bath..
but I couldn’t even finish drinking the hot bath!
2:45 AM - 11 Jun 2015