Stolen directly from Grigory M's question in the definition phase:
http://area51.stackexchange.com/proposals/7526?phase=definition
Stolen directly from Grigory M's question in the definition phase:
http://area51.stackexchange.com/proposals/7526?phase=definition
They both mean "to fix"/"to repair"/"to correct", but 治す is used in the sense of "to heal or cure" ("to fix a disease"). "直す" is used for fixing, not healing.
EDIT: As per Tsuyoshi Ito's correction (confirmed with a bit of googling), I've removed a misleading bit about the object of these verbs.
治す is only used to heal or to cure.
直す has more meanings, it can mean:
1) to fix; to correct; to repair;
2) to replace; to put back as it was;
3) to convert (into a different state); to transform;
Examples:
その本をなおしなさい。= Put back the book where you found it.
次の文章を日本語に直しなさい。= Put the following sentences into Japanese.
==
Source: http://www.csse.monash.edu.au/~jwb/cgi-bin/wwwjdic.cgi?1MUE%E6%B2%BB%E3%81%99