It is notable for being one of the first compositions by the group to reference drugs, though most young fans hopefully missed this at the time. Both Lennon and McCartney admitted that the song was an inside joke about an infamous New York doctor who gave vitamin shots laced with speed to celebrities, though the Beatles implied that he was British with the lyric "My friend works for the National Health."
The recording was made early on during the sessions for Revolver. On April 17th, 1966, the band laid down several attempts at the backing track with the final one, take seven, hitting just the right groove. This utilized the usual line-up of drums, bass and two electric guitars. Overdubs included multiple extra guitar lines from George, maracas (also played by George), piano from Paul (though this was either buried or omitted from the final mix) and a harmonium part played by John for the mock-solemn bridge.
Two days later, on April 19th, they concentrated solely on the vocals. John's lead was recorded with ADT (Artificial Double Tracking). Paul provided a strong harmony vocal from the second verse on, and George joined the others for the bridge, completing the job. All in all, it was a relatively simple recording compared with most others from these sessions.
This song was soon sent along with two other Lennon compositions to Capitol Records for inclusion on the compilation album "Yesterday"...and Today, released in June. Whether those in charge planned it or not, the recording's fadeout/full stop served to nicely set up Paul's famous ballad Yesterday. On the UK album Revolver, released in August, producer George Martin deliberately chose to have this faded ending lead into the fade up of Harrison's I Want to Tell You.
Like most of the band's recordings from 1966 on, they never performed the song live.