Difference Between Drop And Drop Purge In Oracle

Normally, a table is moved into the recycle bin (as of Oracle 10g), if it is dropped. However, if the purge modifier is specified as well, the table is unrecoverably (entirely) dropped from the database.

Oracle Database 10g introduces a new feature for dropping tables. When youdrop a table, the database does not immediately release the space associated with thetable. Rather, the database renames the table and places it in a recycle bin, where it canlater be recovered with the FLASHBACK TABLE statement if you find that youdropped the table in error. If you want to immediately release the space associated with the table at the timeyou issue the DROP TABLE statement, then include the PURGE clause as follows.DROP TABLE employees PURGE;Specify PURGE only if you want to drop the table and release the spaceassociated with it in a single step. If you specify PURGE, then the database does notplace the table and its dependent objects into the recycle bin.NOTE: You cannot roll back a DROP TABLE statement with the PURGEclause, and you cannot recover the table if you drop it with the PURGE clause. Thisfeature was not available in earlier releases.

A link to asktom article: http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:32543538041420

Basically with oracle10, all dropped tables go into recycle bin from where they can be undropped. With purge you basically skip the recycle bin part and you drop the table without an option to undo the action.