Regeneration

Regeneration is the ability of a creature to slowly restore health over time without the need of potions, spells or a rest. Characters with a constitution of twenty and higher will regenerate automatically one HP per x seconds, where x decreases with increasing constitution. Potions, items and spells may apply a regeneration effect/bonus and all sources of regeneration stack (even multiple casts of the spell Regeneration or multiple potions of regeneration).
Much like with poison damage-over-time and such effects, all sources of regeneration (except the one from having high constitution) are sped up by Haste effects and slowed down by Slow effects.
Sources of regeneration for player characters:
*Axe of the Unyielding +3 (1hp/6secs)
*Axe of the Unyielding +5 (1hp/2secs)
*Blackrazor (1hp/5secs)
*Cloak of the Sewers' Troll form (1hp/sec)
*Constitution (ranging from 1hp/60secs at 20 CON up to 1hp/10secs at 25 CON, unaffected by haste and slow effects)
*Cornugon's Revenge (1hp/3secs) 
*Hexxat's Amulet (without the Cloak of Dragomir: 1hp/6secs / with the Cloak of Dragomir: 1hp/18secs)
*Pearly White Ioun Stone (1hp/30secs)
*Peridan (1hp/60secs)
*Potion of Regeneration (1hp/3secs)
*Regeneration (spell) (3hp/sec)
*Ring of Gaxx (1hp/3secs)
*Ring of Regeneration (1hp/6secs)
*Shapechange's Giant Troll form (1hp/sec)
*Shapechange's Greater Wolfwere form (8hp/sec)
*Shapeshift: Greater Werewolf (1hp/2secs)
*Staff of the High Forest (1hp/12secs)
*Trollblood Ioun Stone (1hp/6secs)
*Wong Fei's Ioun Stone (1hp/6secs)
The games use three differently named status effects to show that a character is regenerating, depending on how they gained the ability:
*Regenerate
*Regenerating
*Regeneration
Category:Game mechanics