Note to Twelfth Night, 1.5.198-199, "If you be not mad, be gone"

Because it seems that Olivia would want the young gentleman to "be gone" if he were mad, editors have struggled with this line. In his edition of 1860, Howard Staunton emended it to "If you be but mad, be gone." However, the line can make sense as it stands. Olivia could mean, "If you are not crazy, you will realize that I won't listen to any more messages from Orsino, so go away," or "If you don't excuse your saucy behavior by saying that you are mad, go away." Still, Staunton's suggestion works best with what Olivia says next, which is "if you have reason, be brief," so that the whole passage would mean, "If you are simply crazy, go away; if you have something reasonable to say, be brief."

Imogen Stubbs as Cesario, left and Helena Bonham Carter as Olivia, 1996