Recently I started re-reading Brideshead Revisited, and there are a couple of places where someone with a hangover gets something from the pharmacy to relieve the symptoms. Sebastian, on the morning following his first meeting with Charles, says that he placed himself unreservedly in the hands of Dollbear and Goodall (presumably pharmacists), “and now feels so drugged” that he feels as if the whole preceding night was a dream. In another scene, Rex Mottram gives Charles a “draft” that he “sent round to Heppel’s” for. I’m curious as to what pharmaceutical ingredients would have been in these. I know that nux vomica is sold in homeopathic form for this purpose, by herb and healthfood stores.
In one of the Jeeves stories, he gives the recipe for his famous morning-after remedy, but in that case it seems merely to consist of a few nutritious elements, like egg yolk.