Since the triumphal reception of the ukulele in the US from 1915, this has been a widespread mnemonic for the most common tuning of the ukulele in GCEA (C6):

WordMyDogHasFleas
stringGCEA

This mnemonic has even entered the memory-psychological literature:

In tuning the ukulele, this catch phrase can be sung:
“My dog has fleas —”1)
A somewhat unique mnemonic device is the one to remember the pitches for tuning a ukulele: D, G, B and E.2) The notes are sung but invariably with the curious words: My Dog Has Fleas.3)

Origin

The exact origin of this mnemonic is unknown. In itself, the words do not match the names of the strings. However, I suspect that this is the parody of a well-known 19th century English hymn, Nearer, My God, to Thee. It was already reported at the end of the 19th Jhs. that church-scorn scoffers in the US parodied this song to “Nero, my dog has fleas”.4) This parody was very popular among students in the following years; this was the group that came in contact with the ukulele most intensively.

The first verse of Nearer, My God, to Thee begins:

1st bar2nd bar
Nea-rer, my God,tothee,Nea-rer to thee!
AGFFDDCFAG

The second measure is CFAG, which is almost identical to GCEA when you put the reentrant G to the end and trade F for the E removed by a semitone step. So it was probably originally sung and played as CEA (up the scale) and then G (down the scale).

Probable original notation
031.jpg

Since the word ukulele is probably derived from 'uku “flea” and lele “jumping”, the association with fleas-stricken dogs is easily explained. In any case, there are already numerous allusions to the connection between dogs and ukuleles in the press in the 1920s.

Distribution

Everyday ---
So I was persuaded that I could get a banjo and play it as I did the ukelele. I could use the same tuning which by the way is quite simple. A ukelele properly tuned emits noises, when the strings are struck slowly, like someone saying, “My dog has fleas.” You can't miss it.

Donald Jones in The Franklin Evening Star 18.10.1938, p. 2

Honolulu
Millie sat in a chair nearby practicing with a ukelele and singing: “My dog has fleas — fleas — fleas,” but always the word fleas was off key. (…) “My dog has fleas — fleas — This is the way to tune up a ukelele, you know. My dog has fleas. There, I've got it!”
And Millie began to play …

Lucy Huffaker in: The Rolla Herald 9.2.1939, p. 6

"Flea" String
Niagara Falls, N.Y., May 18 (AP) — A music store owner told this story.
A small boy walked into his shop and said:
“I want to buy a flea string for my ukulele.”
When the proprietor suggested he meant a “D” string, the boy replied:
“No, I don't. When my teacher tunes my ukulele, he sings 'My-dog-has-fleas' and it's the flea string that broke.”

The Gettysburg Times 18.5.1939, p. 1

Say My Dog Has Fleas When You Tune an Ukulele

On July 17, 1939, George Cruesling and Claude Malani filed their copyright to the following song:

David Rose: My Dog Has Fleas
Holiday for Music
Written in a comic vein, “My Dog Has Fleas” will be the David Rose5) original musical piece on the “Holiday for Music” program, Wednesday, at 10:30 p.m., EST, over CBS. Fantasy woven on the four notes that ukelele players warble as they tune up, “My dog has fleas” is another of the rhythmic novelties for which the young composer-conductor is noted.

The Circleville Herald 2.7.1946, p. 11

Hot Footlight Notes From Hotfooting Footrails
Some time ago Rose took an old ukulele effect known widely as “My Dog Has Fleas” when that tiny stringed instrument was a staple on porches and beaches, and arranged the four notes into a complete composition. The notes are simply the tune plucked out by the four ukulele strings without fingering. Rose orchestrated them first in a pizzicato effect, then as a soft and sweeping passage using a large violin choir and brasses, proceeding to other quasi-concert results which are excellent musically and amusing in their sharp evasion of stuffy tradition.

Jack O'Brian, in: The Morning Herald (Union Town, Pennsylvania) 31.8.1946, p. 4

Victor Young (1900–1956) and his orchestra recorded a recording of “My Dog Has Fleas”. It actually starts with the leitmotif GCEA.6)

Of course, after the Second World War, the origin of this custom – the song parody – seems to have been forgotten, so that it was only related to the ukulele itself.

In the episode The Ukulele of The Phil Harris-Alice Fay show, which aired on 30.10.1949 on the radio, Phil Harris presents himself as a ukulele player. A friend visits him and tries to Harris' ukulele My dog has fleas to intone. Harris comments on the weird singing:

Your voice is kind of lousy, too.

Internet Archive

What does “My Dog Has Fleas” mean to you? It's the sentence used in tuning a ukelele. And about ukes, 9 times as many are being manufactured now as before World War II.

173.jpg

Amarillo Daily News 28.3.1950, p. 5

Variants

Good Children Eat Apples

As another English mnemonic, Good Children Eat Apples is common.

Japanese Variants: Hanako-san

In Japan, the female personal name Hanako-san 花子さん is used as mnemonic. Allegedly, the comedian Maki Shinji called this while tuning his ukulele and made it popular.

(Illustration: Ukulele Lesson)
German Variants: Gib Carl einen Apfel

I recommend Gib Carl einen Apfel as a German mnemonic.


1) Young, Morris N.: How to develop an exceptional memory. North Hollywood, Ca.: Wilshire, ca. 1962, S. 121
2) This is the G6 tuning für baritone ukuleles which e.g. Lyle Ritz had used, which is however completely unusual for “normal” ukuleles.
3) Alan Dundes: “Mnemonic Devices”. In: Midwest Folklore Jg. 11, Nr. 3, Indiana Issue (1961), p. 139-147, here p. 144
4) Ferenc Morton Szasz: The Protestant Clergy in the Great Plains and Mountain West, 1865-1915. University of Nebraska Press 2004, p. 38. The journal The Inlander, vol. 17 (1906), p. 13, quotes this song that, in the following years, gained much popularity among students. The Northwestern Dental Journal, vol. 1-5 (1903–08), p. 157, reports for the year 1908: “Some musically inclined Freshman has dedicated a parody on 'Nearer, My God, To Thee' to the class of '08, entitled, 'Hauser, my dog has fleas'.” The same song was also performed in 1910 by the freshmen of Missouri State University: “The song was very touching and called forth many repetitions” (The Savitar, S. 133). In the same year, a newspaper reader complained that young people were parodying old hymns. “A crowd of joy riders passed our house the other night. They were singing something to the air of 'Nearer, My God, to Thee.' All I caught of their words was: 'Nero, my dog, has fleas.'” (The Kansas City Times, 3.6.1910, p. 7) Medical students from the University of California conducted a mock funeral in 1912 at a graduation ceremony, at the end of which “a select choir rendered that sacred song, 'Nero, My Dog Has Fleas,' while the dirt was thrown upon the coffin.” (The Graduate 1912, p. 67) Earl Bishop Downer remembered in 1916 “that old college song, 'Nero, my dog has fleas'” (The Highway of Death, F. A. Davis Company 1916, p. 15). Herbert Asbury confirms that the parody was also known in 1926 and thus throughout the decisive period: Up from Methodism, Alfred A. Knopf 1926, S. 158.
5) 1910–1990. Best known for the title tune to the western series “Bonanza”.
6) Source: Internet Archive. The recording is in the public domain.