By Mark Lamport-Stokes
Poulter, who has been battling a chest infection, was stone last in the tournament at five-over-par 221 after carding a five-over 77 in the third round at Whistling Straits.
"Guys it's a no-go this morning," the 34-year-old Englishman said on his Twitter feed. "Body is not strong enough, had to withdraw. (I'm) gutted. First time I've ever had to do that when feeling I'll.
"(I'm) flying back home to Orlando this morning, my bed is awaiting my arrival. I can't get back quick enough."
Poulter had been scheduled to tee off in the final round of the year's final major with American Jeff Overton who elected to play on his own and briskly covered the front nine in just over an hour.
(Editing by Justin Palmer)