Making poisons and diseases deadlier

[Cicciograna]

Are there homebrewed systems to make poisons and diseases more worrying than they currently are?

[Hanuman]

Yes, it's called not telling the players what poisons actually do to them, then adding lots of visceral description.

[Fako]

I don't know the general consensus on this, but the two problems I see with diseases and poisons are pretty easy to fix anyways: 1) Low save DCs and 2) Long delays between having to save against effects.

For the first, you can simply up the save DC, or take a look at Dungeonscape (page 129) or Book of Vile Darkness (pages 44 & 45) for other poisons, and Book of Vile Darkness (page 29) for other disease options. I've got a Warblade in the group who refuses to touch door handles without the rogue checking them due to some of the poisons in Dungeonscape...

As far as problem two, the long saves between effects (1 minute for poisons, typically 1 day for diseases) means there isn't too big of a rush to get it out of the player's system, allowing the group to finish up their current situation and prepare for it. It's not hard to get access to Remove Disease or Neutralize Poison, unless you're in a low-magic campaign. Best solution I've found is to cut the times between effects down, but it's best to warn the players before doing this.

Also remember: Just because most poisons/diseases act like those in the book doesn't mean that all have to. The Skinshred Swarm in my sig carries a disease that requires a save every hour, as an example. It's also possible to have "vile" poisons that can only have their damage healed while on hallowed ground, or you can make magical diseases that have been designed by their creators to be empowered by Remove Disease (if you want to be evil, that is...)