Mod talk:Reborn/@comment-173.24.124.40-20120505161229/@comment-4674838-20120505162316

To uninstall, you can go to where your copy of Terraria is normally installed and delete the folder, then redownload Terraria through Steam. You will need to find this folder on your computer yourself, because it's different for different systems. By default, it's probably in a location such as C:\Program Files (x86)\Steam\steamapps\common\terraria.

Also, another option that should work is right click on Terraria in your Steam game library, clickProperties, go to the Local Files tab and choose Delete Local Game Content. Then redownload Terraria so you're back to the official version.