Health represents the total amount of damage a Creature can absorb. The Health value is shown on the lower right corner of the creature's card, framed by a green cross. If a creature's Health is reduced to zero or lower, the creature is destroyed and removed from the field.
Health can be reduced by attacks from creatures, Poison, or by Spells and creature abilities that cause damage or reduce health (-Health effects). Health can be protected by Armor, as well as restored by Regenerate, Spells and creature abilities (+Health effects).
When a creature's Health is increased, not only does its current Health go up, but its maximum Health is increased beyond its starting value. The new, higher value is used to determine how much health a creature can gain from Regenerate and healing effects.
For example, if a creature with four starting Health is targeted with Enrage, both its current and starting Health values will increase by three. If the creature later takes damage, it can be healed up to a maximum of seven Health.