Serene Pill

Serene Pill is a pill that can increase Inspiration at the cost of Intelligence and also causes a Brain injury.
Due to its unusual negative Medicine Resistance, consuming additional pills increases the effect of the pill by 50% each consumption multiplicatively. This means that consuming the pill for the third time results in gaining 6750 base Inspiration, reducing Intelligence by 2.25%, and damaging the brain by 1.125%. 
Assuming that the injuries are healed after each consumption, it is therefore only possible to consume the Serene Pill a maximum of 14 times. The 14th consumption will have the effect of the pill reach 194.6x the base amount, damaging the brain by 97.3%. The next consumption will result in >100% damage and therefore lead to death. As the death occurs before the Inspiration gain is made and cancels it, it is not possible to use Resurrection or a Rebirth Pill to make additional gains.