Bernie Sanders needed hernia surgery because of the heft of the tax hikes his proposals would carry, according to Donald Trump.

Sanders, the Vermont senator seeking the Democratic presidential nomination, had an outpatient procedure Monday and was expected to return to work Tuesday. CNN reports Trump joked to a crowd in Macon, Ga., on Monday night about Sanders’ procedure: “You know why? Carrying around too much tax problems.” Trump, the front-runner for the Republican nomination, continued: “Because he’s gonna tax you. He’s gonna tax you. But let’s not even talk about tax problems — he wants to double and triple everyone’s taxes, wants to bring you up to 90%!” Sanders hasn’t given a figure but has said it won’t be as high as the 90% top rate under President Dwight Eisenhower.