If a man can only write well when drunk, I'll tell him: get drunk. And if he tells me that his liver suffers with it, I'll answer: what's your liver? It's a dead thing that lives as long as you live, and the poems you'll write will live without a as long as.
Source, in full
Original: Se um homem escreve bem só quando está bêbado dir-lhe-ei: embebede-se- E se ele me disser que o seu fígado sofre com isso, respondo: o que é o seu fígado? É uma coisa morta que vive enquanto você vive, e os poemas que escrever vivem sem enquanto.
Notes from Wikiquote
English note by the hand of the poet in the same paper sheet: Your poems are of interest to mankind; your liver isn't. Drink till you write well and feel sick. Bless your poems and be damned to you. | Ibid., p. 229