Last drink

This poison is prepared to be mixed with wine. It does not alter the taste but brightens the color very slightly. It reacts with digestive acids and causes nausea, convulsions and abdominal cramps. The victim is then immune to this poison for a week.
A creature subjected to this poison must succeed on a DC 13 Constitution saving throw or be poisoned for 1d8 hours. Each hour, the creature can make a new saving throw. If it succeeds it is no longer poisoned.