Dredge

[Vindog]

So if I dredge and don't have enought cards left do I lose?
Ex,  {Golgari Grave-Troll}

[redwolv]

You can not even use the abiltiy then.

702.51b: A player with fewer cards in his or her library than the number required by a dredge ability can't put any of them into his or her graveyard this way.

[Vindog]

Thanks , also if I dredge instead of drawing to  {Faithless Looting} do I still discard 2 ?

[Oldschoolmtgnoob]

I would interpret it as to replace one of the two cards you draw with the dredge ability, still draw either the first or second card, which ever you didn't dredge on, then discard two

[redwolv]

I would interpret it as to replace one of the two cards you draw with the dredge ability, still draw either the first or second card, which ever you didn't dredge on, then discard two

Exactly this.

[Mr_Fahrenheit]

Actually, you may replace both of your draws with dredge if you wish. The dredge mechanic works for any time you draw a card, for any reason. Even if your opponent makes you draw a card/s you can dredge. For each instance of you drawing a card you may replace it with a dredge.

7.02.50a

Dredge is a static ability that functions only while yhe card with dredge is in a player's graveyard. "Dredge N" means "As long as you have at least N cards in your library, if you would draw a card, you may instead put N cards from the top of your library into your graveyard and return this card from your graveyard to your hand

It doesnt even specify that it has to be your turn.  As long as you are drawing a card, no matter how, when or how many, you may replace each instance of drawing a card with dredge.

[Mr_Fahrenheit]

And yes you would still have to discard to {faithless looting} regardless of whether you drew cards or dredged as the dredge mechanic simply replaces the draw part of the spell, the rest would have to resolve as normal.