A splash weapon is a ranged weapon that breaks apart on impact, splashing or scattering its contents over its target and nearby creatures or objects. Most splash weapons consist of liquids in breakable containers.
To attack with a splash weapon, make a ranged touch attack against the target. Thrown weapons require no weapon proficiency, so characters don’t take the –4 nonproficient penalty. A hit deals direct hit damage to the target and splash damage to all other creatures within 5 feet of the target.
A character can instead target a specific 5-foot square, including a square occupied by a creature. Use the rules for thrown explosives. However, if a character targets a square, creatures within 5 feet are dealt the splash damage, and the direct hit damage is not dealt to any creature.
If the character misses the target (whether aiming at a creature or a square), check to see where the weapon lands, using the rules for thrown explosives. After determining where the object landed, it deals splash damage to all creatures within 5 feet.