Mechanics Berry activation timing in Gen 4

[Dorron]

What type of bug are you reporting? Mechanics

What is the bug?
In gen 4, if you use U-turn into a Poison Point Pokemon (I will assume it's the same with Static and Flame Body), and it procs while you're holding a Pecha Berry (will assume it's the same with Lum Berry), it shouldn't heal the Poison before the switch, but right after the Pokémon is sent out again. In PS, it heals the Poison before the switch.

Are you able to replicate it? If so, how?
https://replay.pokemonshowdown.com/gen4ou-2416402943-b261s6eu4ffy4ktcp9od8y8fyy83knlpw Pelipper is healed of its Poison before the switch.

Here in this drive there are two screenshots showing that this happened to me in a Platinum (Randomized) file. Hippo used U-turn while holding a Pecha Berry and got poisoned by Poison Touch but didn't heal. It got healed after I sent it out again (didn't take a pic of that). It probably is relevant to DPP OU given Nidoqueen is viable.

 

[Hydrametr0nice]

I reported this here. I have a solution in mind, I just haven't started yet.

All Gens Post in thread 'Past Gens Research Thread'

Jul 18, 2025

Berry activation timing in Gen 4

Everybody knows that berries—specifically HP-healing berries—have strange activation timings. In modern generations, healing berries activate after taking damage, except in the case of self-inflicted confusion damage. I already submitted a pull request to fix this timing: https://github.com/smogon/pokemon-showdown/pull/10902

In Gen 3, healing berries activate at the end of the turn.

However, I recently came across a short clip from a Gen 4 video showing a Sitrus Berry activating after a U-turn, after the new Pokémon had already switched...

• Hydrametr0nice

• 

Edit: It's basically done. I just need a few more answers from the Research thread.