Her breakthrough run at the tournament was halted by a defeat to defending champion Sam Stosur on Sunday, but she had previously shown great promise in overcoming Li Na, Kim Clijsters and Samantha Crawford to reach that stage.
She tweeted: “Planned to go shopping on my last day in NYC. Instead, I have food poisoning.”
Robson’s run has seen her tipped to become the first British female in the top 10 rankings since Jo Durie in the 1980s.
The London 2012 mixed doubles silver medallist said: “I’ve learnt I’m good enough to play with these girls and beat them. Going into my next tournaments, I can definitely take the fact I’m up there with the top girls in terms of level.”
Another to exit the tournament is America’s Mardy Fish, who has withdrawn due to health reasons and whose accelerated heartbeat had made a medical procedure necessary in May. World No1 Roger Federer consequently goes straight to a quarter-final with sixth seed Tomas Berdych.