Cleanse is a White Magick spell that cures Disease status from one ally. This White Magick 5 License costs 45 LP to learn, and 20 MP to cast. It is available for purchase at the Phon Coast for 5,800 gil.
In the International Zodiac Job System version, Cleanse is a White Magick 7 License that cannot be bought. It is found in a chest in the Cerobi Steppe's Terraced Bank. Cleanse can be used by three classes: White Mage, Red Mage, and Knight; although Red Mage and Knight can only learn it if they have the Espers Licenses - Red Mage through Shemhazai and Knight through Mateus.