Are these good rules for throwing a potion of healing?

Question

One of my players decided, on the fly, to throw a potion of healing at an ally as they ran past. I had nothing planned so I improvised this rule

A potion of healing has a thrown range of (20/60). If thrown the receiver must use their reaction to make a DC 15 dexterity saving throw to catch the potion. On a failed save the potion shatters on the ground and is unusable, on a critical fail the receiver takes 1d4 slashing damage as the glass shatters in their hand and is unusable.

Should I make the thrower roll a ranged attack roll? What should I do if they threw it at 30 feet? Would I just give the DEX save disadvantage? Also is the DC too high, or too low? Does the 1d4 slashing on a crit fail work?

Just generally is there anything I should change about this or does this work well?

Answer 1

The rule is, apart from some inconsistencies with the existing mechanics, roughly fine. Basically, you're giving your players a new option to use, which is to their advantage - however, the option does have weaknesses that make it rather unattractive for frequent use. Here's some things I'd change:

It should be a free object interaction

You didn't specify whether throwing the potion counts as an action or not. Assuming it is, a word of caution: giving the potion (or any other item) normally (without throwing it) is a free object interaction (listed as an example on Player's Handbook, page 190), and has no risk of failure. Having to spend one's action and the recipient's reaction to throw a potion for those extra 20 feet, and with the additional risk of failure, seems like too steep a cost to me. Consider making the throw a free object interaction.

Neither attack or a saving throw is a perfect fit

Attack rolls are meant for, well, attacking, and don't work at all for situations like this - your party's monk would have a hard time catching the potion with their unarmored AC! Saving throws are meant for resisting harmful effects. Both are poor fits for situations where the two parties (the thrower and the catcher) are collaborating. The difference between a DC 15 ability check and a DC 15 saving throw isn't that big, but maintaining consistency with the core rules makes your house rules easier to remember and understand.

Note that thrown ranges like (20/60) only make sense for attack rolls. Since we're not using those, you'll have to use a different kind of range system.

Be mindful of Goblin Dice

"Goblin Dice" refer to a single die roll determining the outcome of things; sometimes unimportant like the life of a goblin minion, sometimes important to the point where you wouldn't generally want a single die roll to determine them.

The Potion of Healing is likely to be in the category of "too important for a single roll": its primary use in intense situations where one'd like to throw them instead of just handing them over is to serve as an emergency item. A loss of an emergency item, or even a delay in its delivery can be really detrimental to the party. I'd advise not leaving it up to a single die roll, or at very least toning down the effects of failure.

An example of a less painful failure effect is the potion landing safely on the ground, forcing the recipient to use their object interaction to pick it up.

Drop the critical fail

1d4 slashing damage is, in most situations, negligible, and in the situations where it isn't (eg. being down to your last hit point), it's likely to be extremely frustating. It's also worth noting that critical fails are not an official rule in DnD 5e - we're obviously talking about a house rule here, but if you haven't house ruled other saves/ability checks to have critical fails, I don't think the tiny bit of damage is a good place to start.

If you really like having critical fails in your game, consider having the potion breaking be the critical fail case, and landing on the ground intact the normal one. The loss of a potion is a nasty blow against the party's resources and shouldn't be overused, but critical fails are statistically rare enough to not deter using the throwing option too much.

Answer 2

As a GM I hate the idea of thrown transfers in combat, I've seen them abused far too often so my gut instinct says either a flat no, or make them as hard as possible to pull off if they're going to be a thing; the issue isn't so much when you do this with a healing potion but once established as a mechanism the question becomes what can't you throw? Then why can't I throw B if I can throw A?

I think the worst case I ever saw was two characters using a thrown switch to swap and alternately use a Great Sword back and forward across the room. I've also seen it used to expedite looting caches of armour and weapons to direct use in combat which was more chaotic than useful but it wasn't good.

Outside of combat throwing something to another player is usually inconsequential, although it did nearly cost one of my characters about 100,000 credits worth of gun case one time, just a bit of flavour; but when it starts to be used in combat it uses up actions in strange ways while it also shortcuts tactical movement restrictions.

If you're determined to allow such a transfer then you should have a purely fixed range at which such can be coordinated, 15 ft or so maybe, and it should be allowed only when coordination is possible, so characters who cannot see and communicate with each other shouldn't be allowed to use such a transfer.

Obviously the catcher needs at least one free hand and I'd give a DC reduction for a two handed catch as well. A base of DC 15 seems about right to me, not too easy but not so challenging as to prevent it's use. I also like the idea that a critical fail results in wasting the potion but that's because I'm not in favour of the idea generally and want it to be hard and definitely not risk free if you're going to use it.

I think I do agree with @kviiri that it shouldn't cost actions to execute such a transfer but I think there has to be some kind of roll for the catch which is problematic for the reasons he has mentioned. Potion tubes are designed for hard usage so I'd say that unless you want to inflict a critical failure special effect they shouldn't break when simply dropped.