PreventPotions

Turns potions off. Drinking, splash and lingering potions, and tipped arrows are blocked by default. Beacon effects and /effect can be switched off too. Each one is its own toggle, so you can ban splash potions and nothing else, for example.

Paper, Folia and Fabric, from 1.21.1 to 26.3.

What it blocks

The details, including where Paper and Fabric differ, are on What each rule does.

Features

• Nothing gets wasted. A blocked drink, throw or shot leaves the item where it was.
• A pause button. /preventpotions toggle turns all blocking off for an event, then back on.
• Folia support. Every check runs on the thread that owns the player or item involved.
• Fabric build with the same rules and messages.

Install

Requirements

Java 21 for 1.21.x, Java 25 for 26.x. Spigot isn't supported. The Paper jar is a Paper plugin (paper-plugin.yml), so it needs Paper or a fork.

Paper and Folia

1. Put the Paper jar in plugins/.
2. Start the server. plugins/PreventPotions/config.yml is created.
3. Edit it and run /preventpotions reload.

Fabric

1. Install Fabric API.
2. Put the jar for your exact Minecraft version in mods/.
3. Start the server. Settings are in config/preventpotions.json.

The Fabric build only needs to be on the server. Players can join with a vanilla client.

Updating from 1.1

Swap the jar and restart. Your config carries over unchanged. One thing to know: /preventpotions now needs preventpotions.admin. In 1.1 anyone could run it, which meant any player could turn potion blocking off.

config.yml

Paper and Folia. plugins/PreventPotions/config.yml, applied with /preventpotions reload.

prevent

A missing key counts as false.

messages

One per rule, same names, sent to the player when that rule stops them. & colour codes. A missing message falls back to the default text.

Full default file

prevent:
  drink: true
  splash: true
  lingering: true
  tipped_arrows: true
  beacon: false
  commands: false

messages:
  drink: "&cYou cannot drink potions on this server!"
  splash: "&cSplash potions are disabled!"
  lingering: "&cLingering potions are disabled!"
  tipped_arrows: "&cTipped arrows are not allowed!"
  beacon: "&cBeacon effects are disabled!"
  commands: "&cPotion effects via commands are disabled!"

What each rule does

drink

Drinking is cancelled before it finishes. The potion stays in the hand and the player gets the message. Water bottles are potions too, as far as Minecraft is concerned, so they can't be drunk either. Pouring one on dirt to make mud still works, because that's using the bottle on a block rather than drinking it.

splash and lingering

The throw is cancelled and the potion stays in the inventory. On Paper and Folia the rule covers every thrower, not just players: dispensers can't fire blocked potions, and neither can witches. On Fabric only players are stopped.

tipped_arrows

The biggest one, since tipped arrows can arrive from so many places.

beacon

Beacons still work for everything except players. They hand out effects every few seconds, so with this on, players near a beacon see the message each time it tries. If that's too noisy, set messages.beacon to "".

commands

/effect give targeting a player does nothing to them, and the player gets the message. Mobs are unaffected. On Fabric, the command reports the player as a failed target, the same way vanilla reports a player who's immune.

Potions, beacons and commands are separate rules. Blocking commands doesn't block drinking, and the other way round.

Fabric config

config/preventpotions.json. Same keys as the YAML, in two maps. Rewritten on load, so keys added in newer versions appear in old files. Applied with /preventpotions reload.

{
  "prevent": {
    "drink": true,
    "splash": true,
    "lingering": true,
    "tipped_arrows": true,
    "beacon": false,
    "commands": false
  },
  "messages": {
    "drink": "&cYou cannot drink potions on this server!",
    "splash": "&cSplash potions are disabled!",
    "lingering": "&cLingering potions are disabled!",
    "tipped_arrows": "&cTipped arrows are not allowed!",
    "beacon": "&cBeacon effects are disabled!",
    "commands": "&cPotion effects via commands are disabled!"
  }
}

If the file doesn't parse, the server refuses to start and names the file, rather than quietly running with defaults. A /preventpotions reload with a broken file keeps the old settings and tells you why.

Commands

Reference

Toggle

Toggle is a server-wide pause. Every rule stops at once, without touching the config. It isn't saved: after a restart, blocking is on again. Handy for an event night where potions are allowed, as long as you remember to flip it back. Or just restart.

Permissions

All permissions

There's no bypass permission. The rules apply to everyone, ops included. On Fabric, without a permissions mod, preventpotions.admin falls back to permission level 2.

Paper events

There's no Java API. If you're writing a plugin that needs to get along with PreventPotions, this is what it listens to. Handlers marked “skips cancelled” ignore events another plugin already cancelled.

Listeners

Working around it

To let something through in one case, say a custom potion from your plugin, cancel nothing and instead listen at HIGH or HIGHEST and un-cancel the event under your own conditions. PreventPotions runs at normal priority and never checks again afterwards.

@EventHandler(priority = EventPriority.HIGH)
public void allowSpecialPotion(PlayerItemConsumeEvent event) {
    if (isMySpecialPotion(event.getItem())) {
        event.setCancelled(false);
    }
}

That works for every event in the table except PrepareItemCraftEvent and PlayerJoinEvent, which change items directly instead of cancelling, and the arrow-deleting click, which removes the item before you could undo it.

Threads

Each handler runs on the thread that owns the entity or inventory involved. On Folia that's the region thread. Settings are read from a read-only snapshot that's swapped on reload, so handlers never see a half-loaded config.

Fabric internals

Fabric has no events for most of this, so the Fabric build uses a few small mixins. If another mod changes the same vanilla methods, this is where to look.

Mixins

The wraps come from MixinExtras, which ships with Fabric Loader, so they chain cleanly with other mods wrapping the same call. The draw inject returns before any ammo is used, which is why a refused shot costs nothing.

Events

Checking the rules from another mod

me.eyman.PreventPotions.fabric.PotionRules is public:

// true when that rule is on and prevention isn't paused
boolean blocked = PotionRules.blocks(PotionRules.SPLASH);

// same, but also sends the player the configured message
if (PotionRules.deny(serverPlayer, PotionRules.DRINK)) {
    return InteractionResult.FAIL;
}

Rule names: DRINK, SPLASH, LINGERING, TIPPED_ARROWS, BEACON, COMMANDS. Call them on the server thread. Treat it as handy rather than stable, though: it's public because the mixins need it, not because it was designed as an API, and it may change.

Building from source

JDK 21 and JDK 25 required.

cd PreventPotions
./gradlew buildAll

Jars go to build/dist/. paper/ is the plugin, fabric-shared/ holds the Fabric code and mixins, and fabric-1.21/ and fabric-26/ build it per Minecraft version. ./gradlew :paper:check also compiles against the newest Paper API.

FAQ

Can staff be allowed to use potions?

Not with a permission. There's no bypass. /preventpotions toggle turns everything off for everyone. For per-player exceptions you'd need a small plugin that un-cancels the events, see Paper events.

Why can't players drink water?

A water bottle is the potion item with no effect, so the drink rule covers it. Turn drink off if your players need water bottles. Making mud still works either way.

Players get spammed near beacons

Beacons re-apply their effect every few seconds, and each attempt sends the message. Set messages.beacon: "" to block silently.

Do mobs get blocked too?

Beacon and command blocking only affect players. Splash and lingering are different on Paper and Folia: they stop any thrower, so witches can't throw blocked potions either. On Fabric, witches are left alone. Tipped-arrow pickup is blocked for mobs too on Paper.

Does it affect potion effects from food, totems or other plugins?

No. Only the six rules above. A golden apple, a totem or a plugin calling addPotionEffect still works.

Troubleshooting

Common problems

Known limits

• No bypass permission and no per-world settings.
• Toggle isn't saved across restarts.
• On Fabric, tipped arrows aren't stopped in the crafting grid, only cleaned out afterwards.

Support

Questions and bug reports go through the Discord.

Join the Discord

What to include in a report

• Server software and version (Paper, Folia, a fork, or Fabric)
• Your PreventPotions version
• Your config.yml or preventpotions.json
• Exactly what the player did, and what happened
• The console log from start-up