What's the difference between "Concentrated poison damage" and "Poison Damage"?

The amount of poison damage, possibly over a given amount of time.

Is the given amount of time implied? Because there it's not listed. Also, on the poison I made it has 61% weakness to poison for 30 secs, 61 points of concentrated poison damage, and 91 points of poison damage. It seems to do less than normal poison damage. That might just be the ingredients I used though.

maybe its a multiplier. I'm not sure, I haven't done alchemy yet.

Well, the perk says concentrated poison applied to a weapon lasts for twice as many hits. So maybe it's 91 points of damage on the first hit and then every hit after that does 61 damage until the weapon is clean again (2 hits?).

The perk "Concentrated Poison" says that poisons last twice as many hits. I believe that applies to all poisons.