Greater Barghest Poison

[Locotomo]

Hi there,
Where can I find the dc for the Barghests “Fangs(poison)” mutation?

It has the poison tag so I assume these rules apply :

Poison When a creature is exposed to a monster’s poison, it attempts a Fortitude save to avoid becoming poisoned. The level of a poison is the level of the monster inflicting the poison. The poison follows the rules for afflictions found on page 457 of the Pathfinder Core Rulebook.

[Ruzza]

No DC, it's just bonus damage and persistent damage (which is cleared with a flat check). The poison trait notes: "An effect with this trait delivers a poison or deals poison damage." It goes on to note that it may cause an affliction. In this case, it does not.

[breithauptclan]

Another reason to give it the 'poison' tag is for things that are immune to poison. They would also be immune to the extra damage and persistent damage from Barghest fangs. Same with resistant to poison damage.