From the Washington Post:

A U.S. government official said Saleh, who left Yemen on Sunday to seek medical care in Saudi Arabia, “sustained significant burn injuries and shrapnel wounds.”

“His condition is serious, and it’s likely that it will take him a while to recover fully,” the official said. Saleh has burns covering about 40 percent of his body and suffered extensive shrapnel injuries from wood splintered by the rocket attack on his palace, the official said.