Poisons use and gathering components

[Falcon X]

One of my players is really in to Celtic Druidic lore. Thus in our initial questing, she was wanting her character to go into the woods, find some basic poisons like hemlock, grind them into powder and throw them at people and the like. This can unbalance the game, and somehow I feel it's off realistically too.

How should I restrict her while still making her feel like I'm not arbitrarily shutting her down? I don't like to say "You can't do that, because I said so."

So far, I've given her this ruling:

Things like hemlock are generally to be ingested and have little affect on skin contact, which means it would have to be specially prepared to work as an inhalant if your attempt is to throw it at an enemy or make a trap out of it.
Therefore, I offer a few uses of foraging for poisons from herbs:
1. Use them as the ingredients for prepared poisons. This is the intended use by the game and there are rules for it.
2. I will allow you to magically enchant the ingredients into drams of reagents that can enhance your poison spray cantrip. (Will increase the spell level)
3. You can use them in their unmodified form. Ex. Hemlock hidden in food to assassinate someone. Will be less potent and versatile than prepared poisons, but effective when used correctly.

Any ideas of how I can keep her happy while not breaking the game with poisons?

[Daishain]

The ruling you have listed here is reasonable.

Frankly, I'm not entirely satisfied with the poison rules myself, but if she is not willing to see how just throwing hemlock dust around is unrealistic (at least in terms of anything other than a largely ineffective blinding agent), I'm not sure what you can do to keep her happy.

[JFahy]

Maybe give her a chance to nail something with ingested/inhaled poison every
so often (guards leave their food unattended for a bit, or whatever) to make
her happy - but yeah, I think you did the right thing nixing chem grenades.

[Slipperychicken]

Any ideas of how I can keep her happy while not breaking the game with poisons?

Keep the normal craft time for poisons, but require that she succeed Survival checks (DC varies depending on the poison) every day instead of paying for materials? You could also roll randomly to determine whether the desired materials are present in the local environment, or even make her quest for poison ingredients.

Also, I'd imagine that throwing non-contact poison by itself could work if she gets it into the target's mouth, eyes, or similar orifice (suffer disadvantage on the attack roll). Otherwise, she'd have to apply the poison to a weapon, or trick her targets into ingesting it.

And then for the damage, just find whatever poison seems most similar, and use those stats. Obviously hemlock isn't going to be a no-save instant kill effect in 5e.

[Eslin]

She's a druid, she can supply the whole party with poison use anyway starting level 2 - free giant snake poison for everybody!

[Mostlymad]

Easiest way to restrict her is to stick with the costs and time to create poisons. If you make the poison scarce or harder to come by then it will be a resource she has to consciously choose to use or not use, much like spells. It will take days for her to make many poisons so if she runs through them too fast she won't have any for a while. 100g basic poison takes 20 days to craft for ONE dose. Harvesting the ingredients should be either an herbalism/nature check. Basic poison should probably be a DC10 check to harvest. DMG poisons, depending on market cost, might be harder to cultivate or as it says in the DMG "an entire adventure in itself."

You can always insert reasons to reduce an over abusive poisoner. Example I'd use are: interest from a local assassin's/alchemist guild could prompt an adventure as they try to get her to stop/recruit her. Local druid guilds could catch wind and investigate why one of their own is using poisons (an evil act in the eyes of most), etc.

[pwykersotz]

You know, another way to balance this is to refluff weapons with which she is proficient as poisons. Have them deal instant HP damage the same as a weapon of that range. If she's not trying to be abusive and just trying to have fun poison-flinging goodness, that can be accommodated.

[MeeposFire]

A different option is to have the poison the player makes work just like the poison cantrip with limited uses (or exactly as the cantrip and the poison is the material component). We know that the cantrip is not too powerful so essentially you trade time, money, and limited uses to get an additional cantrip.