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Bio is an Attack spell in Final Fantasy VI. It is the more powerful Poison Poison-elemental spell, stronger than Poison, that deals decent poison-elemental damage and inflicts the Poison Poison status on target. Bio is learned by party members through magicite.

Bio is also an enemy ability used by Vampire Thorn, Daedalus, Level 50 Magic, Level 80 Magic, Magic, Magic Master, Master Tonberry, Kamui, Tentacle, Ultima Weapon, Ouroboros, Skull Dragon (Dragon's Den version), Kaiser Dragon, Hidon, and Borghese.

Bio is an added ability to the Scorpion Tail, a weapon exclusive to Gogo.


Party members can learn Bio from magicite. It is taught by Catoblepas at a x8 rate.


As a spell with a power of 53, it deals initial damage with the following formula:

where "Level" refers to the user's level, and Magic refers to the user's Magic stat. The target's Magic Defense and shell play a role in mitigating damage, and the spell can potentially be blocked by Magic Evasion.

Several relics augment Bio's initial damage (along with other spells). If the caster is equipped with an Earring or a Hero Ring, the damage is multiplied by 5/4 (or a 25% increase). If the caster is equipped with two Earrings, two Hero Rings, or one of each, the damage is multiplied by 3/2 (a 50% increase). If the caster equips Gold Hairpin or Celestriad, its MP cost is halved or reduced to 1, respectively.

Because the spell deals poison-elemental damage, the enemy's elemental affinity affects its damage output. If poison is nullified, or the target is immune to poison, the spell will deal 0 damage. If the target absorbs the element, it will heal HP instead of dealing damage. If the target resists the element, it will deal half damage; conversely, if the target is weak to the element, its damage will be doubled.

The spell also inflicts the poison status to enemies not immune, which periodically deals poison-elemental damage to the target over time.


Bio is an upgrade over Poison due to its higher damage and higher hit rate. However, the three comparable elemental spells (Fira, Blizzara, and Thundara) deal more damage for a slightly lower MP cost. This means that, while Bio can deal more damage over time, these three spells are better choices in most cases. Bio is best used against enemies weak to the poison element, and especially ones also vulnerable to the status, as both the initial damage and the status will deal double damage.

As an Attack spell, the player should prioritize teaching Bio to party members with a high natural Magic stat and access to mage equipment. This includes Terra (who can double its damage with Trance, Celes, Relm, and Strago; Mog and Shadow have high Magic stats, while Gogo has access to mage equipment. Though Sabin is best built toward magic damage, his access to Aura Cannon makes him less of a priority than others. Bio is somewhat easy to learn, meaning all party members should eventually be taught the spell to take advantage of its elemental damage.

Bio is the strongest poison-elemental spell in terms of damage output, turn-efficiency, and hit rate. However, later spells are much stronger than Bio, and can likely end fights before the poison status effect comes into play.