Seven-card Stud Hi/Lo is a variant of Seven-card Stud. If you need a quick refresher on the basics of Seven-card Stud, click here.
The betting, ante, and bring-in are exactly the same as in Seven-card stud. At the showdown, the pot is split between the holder of the highest hand and the holder of the lowest hand, if the low hand qualifies.
To qualify for a low hand, you must have five distinct cards (no pairs), with no card higher than an 8. Straights and flushes do not count against you. The best 5 card low hand is A-2-3-4-5 of any suit. The hand is "ranked" by starting with the highest low card. 7-4-3-2-1 would be considered a 7-low, and would lose to 6-4-3-2-1, a 6-low. If two players each have low hands with the same highest card, the next highest card determines the winner. 7-5-4-3-2 loses to 7-4-3-2-1. If there is no qualifying low hand, the high hand wins the entire pot.
The only betting difference is that fourth street does not offer an optional increase in the betting limit, regardless of any pairs on the board. In Seven-card stud Hi/Lo, the first two betting rounds are always at the lower limit, and the last three always at the higher limit.
Just as in the high version of Seven-card stud, each player starts with two hole cards and one upcard; there are then three more rounds of upcards, with betting after each card, and a final downcard, followed by a final betting round. Each player ends up with seven cards: four face up and three face down.
In Seven-card Stud Hi/Lo, each player forms a high hand and, if possible, a qualifying low hand, using any five of his seven cards. Both the high hand combination and the low hand combination can use the same set of cards, but they don't have to. As in Seven-card Stud, aces play both high and low. You may use an ace as a high card for one hand, and as a low card for another.
Information from Full Tilt Poker