It requires a skill check in D&D 4. If you fail, you might kill your friend. Though that usually requires rolling very low and the PC being low on hit points. But that is far from impossible, especially with the "right" disease.The problem with the system is that diseases can range from trivial to super nasty in effects but the cure is automatic and universal. What if the cure disease ritual worked automatically only if the ritual caster's level exceeded that of the disease? A caster of equal or lesser level might have to contest with the disease via a series of skill rolls or something.
This would work great when combined with unknown diseases. Such disorders might have a specific cure that require an adventure to aquire or the PC's can attempt a ritual, not knowing if it is potent enough to be effective. A disease that resists several attempts at ritual cleansing would be plenty scary.![]()
It requires a skill check in D&D 4. If you fail, you might kill your friend. Though that usually requires rolling very low and the PC being low on hit points. But that is far from impossible, especially with the "right" disease.
I don't think it makes sense to make it too hard to cure diseases by default. Diseases of your levels are light encounters or skill challenges of your level - you have a very good chance to make it out succesful. If you want a disease to be dangerous, make it a high level disease, just like dangerous encounters have a higher level.
Does the ritual need the skill check or is that just for trying a cure using the heal skill? I don't have my books handy and disease hasn't come up in our games much yet.
The ritual does require the skill check.
Looking at the specific character, other than using higher DCs a.k.a stronger diseases, there's not much you can do once you get out of heroic. The PCs will at most likely suffer only the one time infection.
Of course, as another poster pointed out, if the PCs are pressed for time ("racing after cultists in a disease infested swamp"), you're likely to get Endurance being more important.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.