[7] Lennon described it as "an 'acidy' song" with lyrics inspired by actor Peter Fonda's comments during an LSD trip in August 1965 with members of the Beatles and the Byrds.

In late August 1965, Brian Epstein had rented a house at 2850 Benedict Canyon Drive[9] in Beverly Hills, California, for the Beatles' six-day respite from their US tour.

Soon their address became widely known and the area was besieged by fans, who blocked roads and tried to scale the steep canyon while others rented helicopters to spy from overhead.

[11] Having first taken LSD ("acid") in March that year, John Lennon and George Harrison were determined that Paul McCartney and Ringo Starr should join them on their next experience of the drug.

Soon afterwards we dropped acid and began tripping for what would prove to be all night and most of the next day; all of us, including the original Byrds, eventually ended up inside a huge, empty and sunken tub in the bathroom, babbling our minds away.

It was a thoroughly tripped-out atmosphere because they kept finding girls hiding under tables and so forth: one snuck into the poolroom through a window while an acid-fired Ringo was shooting pool with the wrong end of the cue.

"[19]As the group passed time in the large sunken tub in the bathroom,[20] Fonda brought up his nearly fatal self-inflicted childhood gunshot accident, writing later that he was trying to comfort Harrison, who was overcome by fear that he might be dying.

[12][nb 2] After this, the gathering settled down as Lennon, Harrison, McGuinn and Crosby sat in the large bathtub discussing their shared interest in Indian classical music.

Crosby demonstrated raga scales on an acoustic guitar and recommended that Harrison investigate the recordings of Indian sitarist Ravi Shankar.

[28][nb 3] Peter Brown, Epstein's assistant, later wrote that, in addition to inspiring Lennon's 1966 song "She Said She Said", the band members' "LSD experiment" in August 1965 "marked the unheralded beginning of a new era for the Beatles".

[20] Author George Case, writing in his book Out of Our Heads, describes the Beatles' subsequent album, Rubber Soul, and its 1966 follow-up, Revolver, as "the authentic beginning of the psychedelic era".

The coda features a canonic imitation in the voice parts, a development of the idea originally presented by Harrison's lead guitar in the verse.

[39] Musicologist Alan Pollack comments that, typically of the Beatles' work, the song's experimental qualities – rhythm, meter, lyrics, and sound treatment on the official recording – are tempered effectively by the band's adherence to a recognisable musical form.

[45] In his commentary on "She Said She Said", music critic Tim Riley writes that the song conveys the "primal urge" for innocence, which imbues the lyric with "complexity", as the speaker suffers through feelings of "inadequacy", "helplessness" and "profound fear".

[65] Harrison also contributed the lead guitar part, incorporating an Indian quality in its sound[62] and providing an introduction that Riley describes as "outwardly harnessed, but inwardly raging".

[68] In his liner notes to the 2022 Revolver: Special Edition, archivist Kevin Howlett states that "It is pretty certain ... that Paul is heard on the original rhythm track containing bass and drums".

"[74] Writing in 2017, Alec Wilkinson of The New Yorker said that "She Said She Said" introduced "circumstances novel to western awareness", a theme that had "no obvious antecedent or reference" in pop music.

[78] In his book on the Swinging London phenomenon, Shawn Levy identifies the album's "trio of tuned-in, blissed-out, spiked and spaced tunes" by Lennon – "Tomorrow Never Knows", "She Said She Said" and "I'm Only Sleeping" – as especially indicative of the Beatles' transformation into "the world's first household psychedelics, avatars of something wilder and more revolutionary than anything pop culture had ever delivered before".

[79] Rolling Stone attributes the development of the Los Angeles and San Francisco music scenes, including subsequent releases by the Beach Boys, Love and the Grateful Dead, to the influence of Revolver, particularly the "conjunction of melodic immediacy and acid-fueled mind games" in "She Said She Said".

In his 1967 television special Inside Pop: The Rock Revolution, he described it as a "remarkable song" and demonstrated its shift in time signature as an example of the Beatles' talent for inventive and unexpected musical devices in their work.

[83] A cassette containing 25 minutes of these recordings, which Lennon had given to Tony Cox, the former husband of his second wife, Yoko Ono, in January 1970, was auctioned at Christie's in London in April 2002.

[87] According to Ian MacDonald,[82] Walter Everett[64] and Robert Rodriguez:[88] Kevin Howlett and John C. Winn write that McCartney played bass on the rhythm track before leaving the studio.