Well, I'm sure most of you who have used potions feel that not to be able to stack them is a drawback.
Damage potions are not really THAT useful because you can only have a maximum of 9 in your hotbar (which means you can't hold anything else.
There are mods like this one for previous versions of minecraft, so I thought I should make one for the newest update.

So here it is, potions are stackable upto 16 (including splash potions). I didn't make them stackable to 64 because then they would be too OP.
I made this mod from scratch, I did not copy other people's work.

This mod is compatible with other mods/Modloader/Forge/etc. There should be no problems with compatibility with any other mod.

Features:

-Potions stackable to 16.

Install instructions:

I'm sure you all know how to install a mod, but here it is:
1) Locate the minecraft.jar file at %appdata%/.minecraft/bin
2) Open minecraft.jar with winrar
3) Copy the mod files into the jar
4) Delete the META-INF folder
5) Enjoy

Minecraft forum link: http://www.minecraftforum.net/topic/1758322-stacking-potions-mod-151/

Mod review (proof that it works):

http://www.youtube.com/watch?v=yPhYhAhrtW0 (review by ki6koanyo)

Older versions:

1.5
Click here (zip)

Feedback is appreaciated.