Water polluted with ghoul parts carries ghoul gut. A creature drinking this tainted water must succeed on a DC 12 Constitution saving throw or contract the disease. Symptoms strike when a victim starts a long rest or next becomes excited, as during combat. A victim suffers severe cramps, and their bowels make sounds like two ghouls fighting. When the symptoms first strike, the victim takes 5 (2d4) necrotic damage. In addition, a diseased victim regains no hit points or Hit Dice from nonmagical sources, including resting or spending Hit Dice. A victim who finishes a long rest can attempt a DC 12 Constitution saving throw. On a successful save, the victim shakes off the disease. Failure deals the character another 5 (2d4) necrotic damage.
A character who succeeds on a DC 15 Wisdom (Medicine) check can also remove the disease from another creature. Doing so requires the character making the check to care for the sick individual during a long rest. The caregiver gains no benefit from that rest.