Unlike its counterpart, No Limit Hold’em, bluffing in Omaha 8 Or Better is not an important strategic consideration. The situations where bluffing succeeds in Omaha High Low are few and far between and in most instances are losing propositions. The main reason for this is the split pot nature of the game. Someone will almost always call a bet on the river believing their low or high hand is good enough to take the pot.
In a typical low limit Omaha 8 game, multiple players (usually between three to seven) see the flop. In these games, you will often find one or more calling stations that are going to call bets with any piece of the flop, even if it is something as bad as top pair weak kicker or fourth nut low. Have you heard the saying “you can't bluff a calling station” – there's a reason that saying exists. You can't!
This doesn't mean that you can't ever bluff in an Omaha 8 game though. Usually, two key factors need to be present in order for a bluff to be successful.
First, there must only be one or two other players in the pot. The more people there are in the hand, the more likely there is someone willing to call a bet on the river on the off chance their marginal hand is good for half the pot or more.
Second, position is of vital importance. If you are first to act, you don't know if the river card helped your opponent or not. By having position, however, you are in most instances going to know because your opponent will have either bet or checked. If for example, the board comes 2-5-K-J-K and it's checked to you on the river, this would be a prime time to bluff because the most likely scenario is people were chasing the low (including yourself) and it didn't arrive. A bet here will take down the pot often enough for it to be a profitable play.
Let's look at one more example of a bluff that works well in Omaha High Low. You have A-2-3-4 and the flop comes 5-7-J with two spades. You are up against two opponents. One player bets and you and the other player call. The turn is a red queen. Again there is a bet and two calls. The river is a 9 of spades making the board 5-7-J-Q-9 with three spades. There are now flush and straight potentials but no lows. Your opponent checks now, as does the other player. Even though you have nothing but a busted low draw, the scary nature of this card could cause the initial better to fold the winning hand. He fears not only the flush but the straight as well. He could be thinking that you either have spades or a hand containing 6-8. Both are logical conclusions to reach. He folds and you rake in a nice pot that you would have lost if you just checked.