Acid Splash 5.5e FAQ FAQ
Does Acid Splash hit allies in D&D 5.5e?
Yes. The 2024 version of Acid Splash affects each creature inside its 5-foot-radius Sphere, not only enemies or creatures chosen by the caster. An ally inside the area must therefore make the same Dexterity saving throw as an enemy and takes the spell’s acid damage on a failed save. The caster must place the Sphere carefully or use another feature that can protect an ally.
The answer changed in practical importance with the 2024 redesign. The 2014 version allowed the caster to choose one or two creatures, making it easy to select enemies while leaving nearby allies alone. The 2024 spell instead uses an area of effect. Once the Sphere is placed, creature allegiance does not determine whether a creature is included.
The Sphere affects each creature inside it
Acid 
D&D Portal - Acid Damage type Acid is a damage type used by attacks,
spells, class features, resistance, immunity, and vulnerability. Full link: https://dnd-portal.com/rules/damage-types/acid/ Splash does not use wording such as “each enemy” or “creatures of your choice.” Its area affects each creature inside the Sphere.
An allied creature is still a creature for this rule. If that ally is inside the affected area, the ally becomes subject to the spell and makes a Dexterity saving throw 
D&D Portal - Saving Throw D20 test rule Saving Throw is a d20 test rule used to resolve
uncertain outcomes during play. Full link: https://dnd-portal.com/rules/d20-tests/saving-throw/.
The same rule applies to neutral or otherwise non-hostile creatures. Acid D&D Portal - Acid Damage type Acid is a damage type used by attacks,
spells, class features, resistance, immunity, and vulnerability. Full link: https://dnd-portal.com/rules/damage-types/acid/ Splash does not distinguish between hostile, friendly, and neutral creatures when determining who is caught in the Sphere.
An ally uses the normal Dexterity save
An ally caught in the Sphere does not automatically succeed and does not receive reduced damage simply because the caster does not intend to harm them.
The ally makes a Dexterity saving throw D&D Portal - Saving Throw D20 test rule Saving Throw is a d20 test rule used to resolve
uncertain outcomes during play. Full link: https://dnd-portal.com/rules/d20-tests/saving-throw/ against the caster’s saving throw D&D Portal - Saving Throw D20 test rule Saving Throw is a d20 test rule used to resolve
uncertain outcomes during play. Full link: https://dnd-portal.com/rules/d20-tests/saving-throw/. On a failed save, the ally takes the same Acid D&D Portal - Acid Damage type Acid is a damage type used by attacks,
spells, class features, resistance, immunity, and vulnerability. Full link: https://dnd-portal.com/rules/damage-types/acid/ an enemy would take.
On a successful save, the ally takes no Acid D&D Portal - Acid Damage type Acid is a damage type used by attacks,
spells, class features, resistance, immunity, and vulnerability. Full link: https://dnd-portal.com/rules/damage-types/acid/ Splash damage because the spell has no half-damage result on a successful save.
Careful placement is part of using Acid Splash
The caster chooses the point of origin, so battlefield positioning is the primary way to avoid friendly fire. Moving the point even a small distance can change which creature spaces are included in the Sphere.
This creates a tactical tradeoff. A placement that catches several enemies might also include an ally, while a safer placement might hit fewer enemies.
That tradeoff is part of the 2024 version’s identity. It can potentially affect more creatures than the 2014 spell, but the caster has less direct control over exactly which nearby creatures are excluded.
Other features can protect an ally
Class features and other rules can modify the normal outcome. The 2024 Evoker Wizard 
D&D Portal - Wizard Character class An Intelligence-based prepared full caster with the largest spell-learning system, ritual flexibility, and subclass traditions focused on schools or specialist theories. Full link: https://dnd-portal.com/classes/wizard/’s Sculpt Spells feature is one example because Acid D&D Portal - Acid Damage type Acid is a damage type used by attacks,
spells, class features, resistance, immunity, and vulnerability. Full link: https://dnd-portal.com/rules/damage-types/acid/ Splash is now an Evocation spell.
When Sculpt Spells applies, the Wizard D&D Portal - Wizard Character class An Intelligence-based prepared full caster with the largest spell-learning system, ritual flexibility, and subclass traditions focused on schools or specialist theories. Full link: https://dnd-portal.com/classes/wizard/ can choose eligible creatures affected by the Evocation and cause them to automatically succeed on their saving throw D&D Portal - Saving Throw D20 test rule Saving Throw is a d20 test rule used to resolve
uncertain outcomes during play. Full link: https://dnd-portal.com/rules/d20-tests/saving-throw/.
Acid D&D Portal - Acid Damage type Acid is a damage type used by attacks,
spells, class features, resistance, immunity, and vulnerability. Full link: https://dnd-portal.com/rules/damage-types/acid/ Splash deals no damage on a successful save, so an eligible protected creature takes no damage. That protection comes from Sculpt Spells, not from Acid D&D Portal - Acid Damage type Acid is a damage type used by attacks,
spells, class features, resistance, immunity, and vulnerability. Full link: https://dnd-portal.com/rules/damage-types/acid/ Splash distinguishing allies on its own.