No, the 10 healing is only upon creature death.
Some interesting uses of this card:
- Inoculate your Otyugh to eat something poisonous
- Armangel decks get better stalling and become able to respond to poison decks
- Various kinds of stall decks can use this for a "soft quint" and backup plan versus poison
- Immolation decks can use this for burst healing, protecting fragile rush creatures, counter to Thorn Carapace, etc
Bottom line, this card is theoretically as flexible as Purify, and works on creatures.
EDIT: What do you think of making this a permanent that protects all friendly creatures AND the player against poison for 3 turns? That would allow it to guard quinted creatures, and the effect becomes a little less situational, but creatures won't grant the 10 HP if they're killed after the 3 turns are up.