Ring of Truth (Magic Ring)

There is little doubt that wearing a ring of truth is a mixed blessing. The wearer can detect any lie told to him, but he is unable to tell any sort of falsehood himself. If the wearer tries to tell a lie, he finds himself speaking the literal truth instead. On the plus side, the wearer is able to discern the last lie told by another—in fact, the power of the ring causes the voice of the liar to rise to a falsetto.
If the wearer of the ring encounters magic that enables falsehoods to be spoken without detection (such as an undetectable lie spell or a 
philter of glibness), no lie is detected. However, the ring wearer will find himself unable to hear the voice of the person so influenced, whether or not he is trying to listen. This, of course, reveals the lie indirectly.
Category:DMG Magic Items
Category:Encyclopedia Magica Magic Items
Category:Magic Items
Category:Magic Rings