== Fim de carreira ==
John Barrymore desmaia em seu barco, "''The Mariner''", em 1929, ao largo da costa do [[México]], quando em lua-de-mel com sua mulher Dolores, requerendo cuidados médicos. Muitos dos seus problemas de saúde ocorridos após este fato advem do consumo de bebidas nocivas e mesmo venenosas durante o período da [[lei seca nos Estados Unidos|Lei Seca]] nos Estados Unidos. Ao final dos anos 1930, Barrymore começa a ter problemas para memorizar suas falas e a redução de suas habilidades ficam visíveis em um teste para as telas feito para uma versão abortada de "[[Hamlet]]" (1934). A partir de então, Barrymore insiste em interpretar seus papéis com o uso de cartazes com o texto. Ele executa sua última façanha heróica ao interpretar um [[Mercúcio]] envelhecido no filme da [[MGM]] "''[[Romeu e Julieta (1936)|Romeu e Julieta]]''" de 1936.
Barrymore collapsed on his boat, ''The Mariner'', in 1929 off the coast of Mexico while on honeymoon with wife Dolores, requiring admittance into doctor's care. Much of his newly occurring health problems most likely stemmed from his consumption of bad and sometimes nearly poisonous illegal alcohol during the period of [[Prohibition]] in the United States. In the late 1930s, Barrymore began to lose his ability to remember his lines, and his diminished abilities were apparent in a surviving screen test that he made for an aborted film version of ''[[Hamlet]]'' in 1934. From then on, he insisted on reading his dialogue from [[cue cards]]. He gave one last bravura Shakespeare performance, as an overage [[Mercutio]] in the 1936 MGM ''[[Romeo and Juliet (1936 film)|Romeo and Juliet]]''. He continued to give creditable performances in lesser pictures, for example as Inspector Nielson in some of [[Paramount Pictures]]' [[Bulldog Drummond]] mysteries, and offered one last bravura dramatic turn in [[RKO]]'s 1939 feature ''[[The Great Man Votes]]''. After that, his remaining screen roles were broad caricatures of himself, as in ''The Great Profile'' (with "Oh, Johnny, How You Can Love" as his theme music) and ''World Premiere''. In the otherwise undistinguished ''Playmates'' with band leader [[Kay Kyser]], Barrymore recited the "To Be, or Not to Be" soliloquy from ''Hamlet''. In 1937, Barrymore visited India, the land where his father had been born. In his private life, during his last years, he was married to his fourth and last wife, Elaine Barrie, a union that turned out to be disastrous. His brother Lionel tried to help him find a small place near Lionel's house and to convince him to stay away from impetuous marriages, which usually ended in divorce and put a strain on his once large income.
He was known for calling people by nicknames of his own creation. [[Dolores Costello]] was known in his writing alternately as "Small Cat," "Catkiwee," "Winkie", and "Egg." He called Lionel "Mike", and Ethel called John "Jake". He called Blanche Oelrichs "Fig" and called their daughter Diana "Treepeewee".
Barrymore collapsed while appearing on [[Rudy Vallee]]'s radio show and died some days later in his hospital room. His dying words were "Die? I should say not, dear fellow. No Barrymore would allow such a conventional thing to happen to him." [[Gene Fowler]] attributes different dying words to Barrymore in his biography ''Good Night, Sweet Prince''. According to Fowler, John Barrymore roused as if to say something to his brother Lionel; Lionel asked him to repeat himself, and he simply replied, "You heard me, Mike."