What happened to Jay Leno today? Radio said he was hospitalized. (4/23/09)?

Jay Leno was hospitalized briefly for observation, but he has been released now. The article I read made some reference to food poisoning, but I am sure once he is back on his show (hopefully Monday night) he will make some reference to it and the reason behind it. I believe it's the first time he's missed the show's taping due to illness since he took over in 1992.