When you are injured by a contaminated attack, touch an item smeared with diseased matter, or consume disease-tainted food or drink, you must make an immediate constitution saving throw. If you succeed, the disease has no effect--your immune system will fight off the infection. If you fail, you take damage after an onset (incubation) period. Once per day afterward, you must make a successful constitution saving throw to avoid repeated damage. Two successful saving throws in a row indicate that you have fought off the disease and recovers, taking no more damage. These constitution saving throws can be rolled secretly so that the player doesn't know whether the disease has taken hold.
Following are a few examples of possible disease types.
| Name | Infection Type | Save DC | Onset | Effect |
|---|---|---|---|---|
| Blinding Sickness | ingested | 16 | 1d3 days | 1d4 Str damage, if more than 2 Str damage, target must make an additional Con save or be permanently blinded |
| Bubonic Plague | injury or inhaled | 17 | 1 day | 1d4 Con damage and 1 Cha damage and target is fatigued (level 1) |
| Cackle Fever | inhaled | 16 | 1 day | 1d6 Wis damage |
| Demon Fever | injury | 18 | 1 day | 1d6 Con damage, target must make a second Con save or 1 point of the damage afflicted instead |
| Dengue Fever | injury | 12 | 1 week | 1d4 Dex damage |
| Devil Chills | injury | 14 | 1d4 days | 1d4 Str damage |
| Dysentery | contact or injury | 16 | 1d3 days | 1d6 nonlethal damage and target is fatigued (level 1) and staggered |
| Filth Fever | injury | 12 | 1d3 days | 1d3 Dex damage and 1d3 Con damage |
| Ghoul Fever | injury | 13 | 1 day | 1d3 Con and 1d3 Dex damage |
| Malaria (Jungle Fever) | injury | 18 | 1d3 days | 1d3 Str damage and 1d3 Con damage and target is fatigued (level 1) |
| Mindfire | inhaled | 12 | 1 day | 1d4 Int damage |
| Red Ache | injury | 15 | 1d3 days | 1d6 Str damage |
| Shakes | contact | 13 | 1 day | 1d8 Dex damage |
| Sleeping Sickness | injury | 14 | 1d2 days | 1d4 Wis damage and target is fatigued (level 1) |
| Slimy Doom | contact | 14 | 1 day | 1d4 Con damage, target must make a second Con save or 1 point of the damage is afflicted instead |
| Tetanus | injury | 14 | 1d6 days | 1d4 Dex. Each time someone takes Dexterity damage from tetanus, there's a 50% chance his jaw muscles stiffen, preventing speech and the use of spells with verbal components for the next 24 hours. |