Useless! Absolutely useless! The curative isn't going to meet our mistress' demanding standards if it simply kills the person who ingests it! If we were trying to create a new poison, then we'd be wildly successful. But that isn't the task at hand.
Reduce the amount of dried corpse blood and try again. And watch the temperature in those cauldrons. One of them was dangerously close to boiling over—and I for one have no desire to be drenched in a spray of boiling curative.