Boil Release (沸遁, Futton; Viz "Vapour Style") is one of the two advanced naturekekkei genkai of Mei Terumī and is made up of techniques that combine fire and water-based chakra to create a powerful corrosive vapour capable of dissolving anything. The user is also able to control the range and level of the vapour's acidity. Not only is it dangerous to be near, but as being gaseous, it can cover a considerable range shortly, and go through small spaces. It also stays in the air, so it can potentially deal continuous damage if the enemy is trapped or knocked back into its range.
The only seen technique of Boil Release, Skilled Mist Technique, demonstrates that this kekkei genkai is strong enough to dissolve Susanoo's ribs; an impressive feat, as Sasuke has stated that Susanoo is even more of an absolute defence than Gaara's Shield of Sand. It however has the inherent flaw of being able to harm allies, so it is critical to control the level and range of the attack, and use it in a smart area.
Despite the name of this nature, it does not manipulate boiling water, nor does it boil other things. The name is more symbolic, representing the names of the natures used to create this nature. It is also symbolic of the appearance and effect of this nature, as the corrosion seen is similar to hot water burning something.
The name might also be a reference to the exothermic properties of many corrosive agents (sodium hydroxide etc.), which corrode as much as they boil whatever they touch.