Amulet of Health

[Estralita]

Okay, I've been building a level 10 Bard, and have been given access to various Magic Items. One of the items I'm is considering is the Amulet of Health, which sets my character's Con score to 19. The thing I want know is if that effects my HP total. So, does it, either retroactively, or after leveling up after finding it?

[CantigThimble]

"If your Constitution modifier changes, your hit point maximum changes as well, as though you had the new modifier from 1st level."

It's all retroactive. When you wear the amulet you have HP like it was 19 from level 1. When you take it off it's like you never had it at all.

[RickAllison]

Indeed. My level 7 Monk jumped from 27 HP to 69 (yes, I made the cardinal sin of dumping CON).