It yields a positive Elixir trade against Poison if your opponent places it down. It nullifies the Poison's effects for the most part as the healing per second of the Heal is greater than the damage per second of the Poison, but at equivalent levels the Poison will do more total damage than the total healing capability of a single Heal, because the duration of the Heal is much shorter than that of the Poison's.
The Heal Spell is also effective against the Fireball if the Fireball doesn't one-shot the troops.
The Heal Spell can heal low-health troops when they're targeting a Crown Tower such as a Wizard, Musketeer, or Inferno Dragon to continue dealing heavy damage towards the Tower, as it will surprise the opponent if it remained unused up until then. This is especially deadly when used with an Inferno Dragon, as this will also give it enough time to reach maximum damage and must be countered very quickly which sometimes is not possible.
If the opponent Zaps the Lava Pups from a Lava Hound, Heal can be used to heal the Pups and they will continue to do heavy damage to the opponent's tower.
Healing troops that the opponent would normally ignore and let the Crown Tower defeat can catch the opponent off guard and result in the Tower taking significant damage.
While the Heal has healing capabilities, it does not heal any troops that have been destroyed. Also, it cannot heal troops over their original health. Once the troop has been fully healed, it will not be affected by the Heal. If the troop is eliminated by a particular attack in one hit, the Heal will be incapable of doing anything. For example, Skeletons that are under an enemy Poison cannot be kept alive using a Heal unless the Skeletons are sufficiently leveled such that they do not die in one pulse of the Poison.
A possible strategy would be to use a Miner and a Minion Horde with a Heal, but only if the opponent does not have Arrows or any other high-damage spell, excluding Lightning. If the enemy uses a Zap, a Princess, or Ice Spirit, the Heal will keep the Horde alive and it will continue attacking the Tower. This would work with a Goblin Barrel too if the opponent's counter does not one-shot the Goblins.
Heal was featured in its own Special Event Challenge, the Heal Draft Challenge, which started on 28/4/17. By achieving 6 wins, a one-time reward provided the player with Heal cards, with more Heal cards obtainable at 12 wins as another one-time reward.
The Heal card was added to the game on 1/5/2017.
On 12/6/17, a Balance Update made it so that multiple Heals now stack.
On 11/8/17, a Balance Update decreased its duration to 2.5 seconds (from 3 seconds). This also fixed inconsistencies where the Heal healed either six pulses or seven pulses; it will now pulse exactly five times, in effect decreasing its effectiveness by two-sevenths.
Heal is one of the three spells that don't affect buildings. The other two are Tornado and Clone.
It is one of the five Elixir spells from Clash of Clans to also be in Clash Royale, the others being the Lightning, Rage, Freeze, and Clone.