The medicine Ye Qingxuan gave them was made of 99% saltwater and 1% his blood. The blood, rich in stone of sage and purifying music theory, was the best antidote.
Upon entering the human body, the power in the blood would multiply automatically to kill all parasites and supply with the body with energy, Qi, and blood.
Those in good condition would sleep all their problems away after taking the antidote, while those in poor health may have symptoms like vomiting and diarrhea. In the worst case, they might get seriously ill due to the rebuilding of their immune system.
For those who had been infected for too long, no cure was possible. For them, there was nothing that Ye Qingxuan could do. The purifying medicine, however, would end their endless nightmare and suffering, and wake them up from the madness for a short time.
They would live their last hours with a clear mind.
And then, they would have to face their death.