Trying to remember book that used to be on here

Hi there,

I used to be a moderator here, but haven't posted in a really long time (mostly because I had 4 kids and was too busy!) I'm going nuts trying to remember the title of this book I keep telling my husband about. It used to be advertised here, and I bought it through this site. It had a purple cover and was about a guy who found out about a secret military experiment to remove the ability of humans to communicate using symbolic language. The soldiers who were experimented on went crazy, but then when they released it to the general population, it actually liberated humans from the ruling elite. There was one bit I remember where the main character was poisoned with a vial of poison ivy oil. Does anyone know what I'm talking about? I don't know if skip is still the owner of this site, but if so maybe he knows.

Anyway, I'd appreciate any help!!