Can you create poisons/effects with a Herbalism Kit proficiency?

Question

I am curious as to how far herbalism kits can be pushed.

In the PHB (p. 153), it says about the herbalism kit:

This kit contains a variety of instruments such as clippers, mortar and pestle, and pouches and vials used by herbalists to create remedies and potions. Proficiency with this kit lets you add your proficiency bonus to any ability checks you make to identify or apply herbs. Also, proficiency with this kit is required to create antitoxin and any potion of healing.

In XGE (p. 82), it says about the herbalism kit:

Arcana. Your knowledge of the nature and herbs can add insight on your magical studies that deal with plants and your attempt to identify potions.

Investigation. When you investigate an area overgrown with plants, your proficiency can help you pick out details others might miss.

Nature and Survival. When you travel in the wild, your skills make it easier to identify plants [...]

Identify Plants. You can identify most plants with a quick inspection of their appearance and smell.

This is great when you're looking to make antitoxins and potions of healing/penicilin and all the good stuff, but I am curious to know about the other side of herbology; such as identify poisonous berries, mushrooms, herbs and all the other remedies that herbalists need to know about to avoid making a poison by mistake.... wouldn't proficiency in herbology not help in that way too?

More specifically, given that nature itself is a two-sided coin, with medicinal plants offering hallucinogens, paralysis, poison, inflammatories, etc, wouldn't a PC who is proficient with herbalism kits also be able to create plant/nature-based poisons and potions of special effects much like one proficient with poisoner's kits?

As a player, this can give some interesting options, such as mixing potions of healing with potions of sleep applied to a large gaping wound to help prevent the wound from reopening right away or using potions based on mushrooms to coat your weapon/ammunition and cause the enemy to trip out and cast/swing wildly, or even numb their bodies so they can no longer fight and/or talk...

Though I agree that these would have to be plant-based, and thus most likely would not consider wasp farming or toad slime, I'm wondering why the PHB and XGE only focus on the positive benefits of herbology in this matter...

Answer 1

It would not be wise

The Poisoner's Kit is designed to do exactly what you want to do and fairly safely. The Assassin rogue's 3rd-level Bonus Proficiencies feature (PHB, p. 97) grants them proficiency with the Disguise Kit and Poisoner's Kit. So by making the Herbalism Kit more powerful, you are weakening the Poisoner's Kit and the Assassin subclass.

An example of what could happen:

Let’s look at a level 3 Scout rogue with an Herbalism Kit vs. a level 3 Assassin rogue with a Poisoner's Kit.

At Level 3, a Scout rogue gets the Survivalist feature (XGtE, p. 47):

you gain proficiency in the Nature and Survival skills if you don’t already have it. Your proficiency bonus is doubled for any ability check you make that uses either of those proficiencies.

By being proficient in the Herbalism Kit, you know all beneficial and harmful plants and you have expertise in finding them. The Kit also has leather gloves for harvesting the poison; leather gloves basically make you immune to poison (sarcasm). And because healing with plants is just the other side of the coin to hurting with plants, you are able to make poison. In fact, you are proficient in making healing potions and likely plant-based sleeping aids - nice, you just created a synthetic Drow Poison without ever having to have heard of Drow Poison or the Drow. You could even make a super deadly poison with no cure! ...Wait, why is the room spinning and so cold?

At level 3, an Assassin rogue gets the Bonus Proficiencies feature, which grants them proficiency with the Poisoner's Kit. Per XGtE p. 83, the Poisoner's Kit allows you to apply poisons and create them from various materials. You can identify poisonous plants and animals. And it lets you handle poisons: "Your proficiency allows you to handle poison without risk of exposing yourself to its effects."

In the above example the Herbalism Scout outclassed the Poisoner Assassin - but without a proficiency in a Poisoner's Kit, you will likely be poisoned during the harvesting, creating, and applying of the poison.

Answer 2

The Herbalism Kit cannot create poisons... but D&D has an item for this: the Poisoner's Kit

The Poisoner's Kit is the equipment required to make poisons in the game rules. The game designers chose to separate out making beneficial potions from poisons and related knowledge (for unspecified reasons).

The two kits are pretty similar, but not identical (XGtE, p. 82-83; emphasis mine):

Components. An herbalism kit includes pouches to store herbs, clippers and leather gloves for collecting plants, a mortar and pestle, and several glass jars.

[...]

Components. A poisoner’s kit includes glass vials, a mortar and pestle, chemicals, and a glass stirring rod.

Notably the inclusion of "chemicals and a glass stirring rod" in the poisoners kit suggests that making poisons in game is more complicated and specialised than making healing potions and treating wounds.

Proficiency with the Poisoner's Kit (as described in Xanathar's Guide to Everything, p. 83) gives you the ability to make poisons, handle them safely (i.e. don't poison yourself), but also to identify and treat poisons:

A poisoner’s kit is a favored resource for thieves, assassins, and others who engage in skulduggery. It allows you to apply poisons and create them from various materials. Your knowledge of poisons also helps you treat them.

It also enables you to:

• identify poisonous plants and animals
• inspect and investigate poisoned objects safely

You probably don't want to be mixing the two using the same kit

Another (RP) reason to keep them separate is simply that you don't necessarily want to make your healing potions using the same bit of kit that you just made a poison from.

Doing that could (and in this DM's opinion... would) open you up to the risk of accidentally poisoning yourself when you are trying to make a healing potion. This could be justified pretty easily, for example:

• you didn't clean the kit out properly before making your healing potion
• healing potions may require no impurities for them to function properly
• etc

But what if I do it anyway?

If you choose to allow it anyway you are increasing the availability of crafting poisons in your game. Currently there aren't a whole lot of ways in the game to get lots of tool proficiencies.

By effectively combining two tools into one (by allowing the Herbalism Kit to make poisons) you are reducing the opportunity cost for your players to have to choose between the two. This should also have an in game effect on the availability of potent poisons (as everyone with a Herbalism Kit proficiency in your game can now create poisons!).

Finally, you would reduce the ability of the authorities to "prove" someone was a poisoner by not requiring a separate bit of kit (I swear g'ovner, I was just making some healing potions. Legitimate business that is!).

Answer 3

Short answer is: no. Rules as written, herbalism kit proficiency doesn't give you the ability to create anything but Anti-Toxins and Healing Potions. If you're wondering why the PHB focuses on only the positive side, it's because they are trying to balance the game. (More poison means more damage output.)

Long answer is: heck yeah it can! Anything that heals can harm in heavy doses. I'm sure if you pumped enough Healing Potion into a person it would kill them. Only problem is that you'll have to go homebrew, since there's no material for actual crafting in any of the books, besides the arbitrary trading of coin for the item. If your GM is more into realism than character-balance then it should be easy to sell them on the material.

There's a lot of good homebrew material specifically on this topic; I'll link some that I've found on my journeys:

• "Herbalism and Alchemy" by Dalagrath
• "Kingsmill Materia Medica" by MonarchFactory (Dael Kingsmill)
• My own Herbalism Designs