Wish Powder is the Alchemic Salt which was made from the herbs which went into the Universal Fluid Condenser. It was then blessed with multiple spells for unlimited potential and connection with the divine.
Many protections were added to this to ensure that wishes made with the wish powder would manifest in alignment with the highest good. In short this is probably the safest form of wishing you can do. Unlike other spells or even just personally made wishes, wishes made with Wish Powder are protected from user mistakes and ignorance as much as possible. Wishing for something unhealthy will likely result in the result looking a lot different than the wish maker intended, but power will have been brought to the problem and a solution will be found.