Piven told David Letterman last night that he not only had mercury poisoning, but a host of other ailments as well.

Last night on the Late Show, Piven said “20 years of eating only fish” also lead to Epstein-Barr, heart arrhythmia, and back spasms. Piven also says that he got the best tests in the world at Quest Diagnostics, which can be found on just about any street corner in Manhattan.

He’s sticking by his story why he couldn’t continue doing eight shows a week of Speed the Plow, and a arbitrator recently cleared him of any wrong-doing in leaving the Broadway show two months early. Because every celebrity becomes a crusader for the disease he suffers from, Piven is now fighting the injustice of fetid fish across the globe.

Dave was very sympathetic to his condition, and the interview couldn’t be classified as anything but softball. Piven even got in a few good laughs.

Tags | celebrity, jeremy piven, Video