dealing with duplicate content in wordpress site

HI,
A client wants to start selling wordpress sites that are preloaded with products and content. He has over 2.000 products on the site. It's a site we've redone in wordpress that was coldfusion based. Is there any easy automated way to alter the product descriptions without having to edit each one manually? The descriptions will still need to be understandable. How bad can duplicate content hurt you in google?

Corn