Stacking buffs question.

[Soul Reaver]

So, my DM is being stubborn again. He goes by the rule of 'if it has the same name, the buffs don't stack', so for example if you wear two armors, it doesn't matter, the bigger AC bonus is the one used.

And that's fine and dandy.

But he claims that things like rage, mutagens, enlage person, potions, spells and stuff don't stack with one another, even though rage is a morale bonus, mutagen is alchemical bonus, enlarge person is size bonus, etc.

What's the ruling here?

[CampinCarl9127]

Could you perhaps be a little more specific in what abilities you are wanting help with? The question seems very broad and vague.

[Soul Reaver]

Oh, sorry.
My question is mainly, do these bonuses stack together or not?
Like for example, casting enlarge person on a raging barbarian -would- give a +2 to strength, or having a barbarian somehow using a mutagen would give him +4 from strength and +4 from the mutagen, etcetera.

[Deighton Thrane]

The same kind of bonuses don't stack, except usually dodge bonuses, or unnamed bonuses. So morale, alchemical and size bonuses to strength all stack. But a belt of giant's strength +2 and bull's strength don't, since they're both enhancement bonuses, you just take the greater.

[kinevon]

Stacking
Stacking refers to the act of adding together bonuses or penalties that apply to one particular check or statistic. Generally speaking, most bonuses of the same type do not stack. Instead, only the highest bonus applies. Most penalties do stack, meaning that their values are added together. Penalties and bonuses generally stack with one another, meaning that the penalties might negate or exceed part or all of the bonuses, and vice versa.

If the bonuses have different types, or are untyped bonuses from different sources, they usually will stack. There are a few variations that limit some of them.

Barbarian Rage wrote:

While in rage, a barbarian gains a +4 morale bonus to her Strength and Constitution, as well as a +2 morale bonus on Will saves.

Alchemist's Mutagen wrote:

Upon being imbibed, the mutagen causes the alchemist to grow bulkier and more bestial, granting him a +2 natural armor bonus and a +4 alchemical bonus to the selected ability score for 10 minutes per alchemist level.

Enlarge Person wrote:

The target gains a +2 size bonus to Strength, a –2 size penalty to Dexterity (to a minimum of 1), and a –1 penalty on attack rolls and AC due to its increased size.

Potions would be whatever type the spell in the potion is.

Spells, again, would be whatever type the spell says.

Stuff is a bit too general to define.

[Deighton Thrane]

BTW, this is all found in the getting started section of the Core Rulebook, under common terms.

[CampinCarl9127]

As long as they are different kinds of bonuses (morale, size, alchemical, etc.) then they will stack.

I would talk with your GM. This may be a houserule he uses, or it may simply be a misunderstanding of the rules.

[Soul Reaver]

Oh, I've been debating with him for like an hour. He's misunderstanding the rules, hopefully showing him this thread will help.
I mean, I wouldn't mind if it was a houserule, but he's just not believing me.
Many thanks to all of you, and my apologies if this has been asked before!