"May the Old Faith be on your side during this battle. Here. Take some fragrant herbs you can chew if the smell of the trogs is too much to bear. This should help you bear most of the stench."
You can chew on these for four hours, in bites of one hour each (need not be consecutive and some portions can be saved for later). This provides +2 bonus against the trog's stench ability per portion chewed on; i.e. if you chew two portions, you get +4; three portions, +6, etc. but this means you will spend those multiple portions over the course of one hour. Chewing 3 or 4 portions at the same time disrupts speech and leads to a 20% chance to fumble a spell if that spell has a verbal component.