I must say I'm disgusted of this game, they just swarm you with a dozen monsters each time and call it the end-product. I mean if I wanna fight I'll just mod BG and put whatever monsters I want to fight in it.

Now could anyone tell me how to deal with masses of trolls? Do I have to memorize all level-2 magic as Melf's Acid arrow and buy tons of lamp oil or is there any other way to deal with them? Thinking about some weapons that can deal fire damage. I'm at the beginning of Chapter 3.

Thanks in advance!

(BTW I do know that fire and fire magic also hurt trolls)

Oil works great; I never even had to buy any, there's more than enough discovered as loot to finish off trolls. There are also a couple weapons that deal fire damage, though most only do so randomly so you may have to smack the trolls a few times before they go down.

There are no trolls in Chapter 3, however. They're fairly common enemies in chapter 2 and chapter 5, not quite so much in the other chapters.

Don't feed them.

In all seriousness, Fireballs, Scorcher for when you have them in a row, and any wands that have those effects are the best solution. Other than that, I'd recommend having one person carry a fire weapon, instead of wasting money on fire arrows or flasks of oil, and have them do a sweep on all fallen trolls.

Thanks. I guess I need to find a weapon that deals fire dmg asap as Chapter 3 does contain lots of snow trolls. Thanks. Fireball is not very useful as I have to pick them one by one. So I decided to memorize fire arrow, which is more useful. I'll check gamebanshee for weapon guides.

Are you sure you've got the chapter numbers right? Chapter 3 (the Severed Hand) has no trolls.

Have you tried running away? Don't laugh, it works for me. I haul ass to the nearest "loading area" and then come back, hit, run away, come back, hit, run away and so on.

To OP:
The above is correct. Chapter 2 (Dragon's Eye) is where all the Ice (and other) Trolls are -- remember that the 'first' chapter is actually the prologue.

1st - Prologue (Easthaven)
2nd - Chapter 1 (Kuldahar, Vale of Shadows)
3rd - Chapter 2 (Dragon's Eye)
4th - Chapter 3 (The Severed Hand)
5th - Chapter 4 (Dorm's Deep)
6th - Chapter 5 (Wyrm's Tooth)
7th - Chapter 6 (Lower Dorn, Easthaven)

My apology as I'm actually playing IWD2, not IWD. Sorry for that.
And this circling around Fell wood for three times is simple disgusting. I need to get this game done and never come back. Anyway, on route! Yes it probably works, but considering the number of trolls...(just encountered around two dozens, maybe more ahead).

I hope you collected all those fire potions that the lizardmen on the level above dropped? They sure come in handy when dealing unto trolls their death and final end. In addition to fire weapons you can also use Acid Arrows.

True; all my suggestions were intended to address groups of fallen trolls, or trolls that were near death that would have been knocked down and destroyed by what I suggested, but it doesn't seem all that clear now that I reread it.

I use Web, Entangle, and Spike Growth for IWD 1. Similar spell brew for IWD2 (add Grease in the mix). This keeps them, for the most part, nice and confined. Some will get through, but you'll have a much easier time of it than if you don't use AoE spells. At that point in IWD2 you should have access to a couple weapons that deal fire damage as well, so equip them on your tanks. As noted, have your mages memorize some fire spells that target individuals. And fire/acid arrows do the trick quite well too.

Not sure what your party consists of but mine are usually fighter heavy so this is what happens for me. My fighters (melee and ranged) tend to drop trolls pretty quick so what the targetted troll falls, I don't finish him off right away, I use his body to block the trolls behind and attack the two trolls on each side of the fallen troll until they drop. When the trolls start to bunch up (assuming there's a lot of trolls), you can then use burning oil potions on the first troll you dropped, killing the 3 or so surrounding fallen trolls in one go, throw a few behind as well and weaken them. It always worked for me which is why I hoard those oil potions. It really depends of the situation and how many oil potions I have, if there's only 3 or 4 trolls it's pretty easy. But if I get swarmed with trolls and I have the potions, I do the above.

EDIT: In The fell wood there isn't enough troll to make what I said worthwhile. In that case, I just drop them as normal while everyone else picks another target and my archer fire arrows him down. Thhe fell wood is annoying but you can always look online for the correct way out of it.