How does one treat certain diseases using the Most Beautiful Names of Allah?

The correct way to seek healing through the names of Allah the Almighty is by supplicating to Him with them, such as the sick person saying: "O Allah, heal me, O Healer (Ya Shafi)," or by reciting them over water and drinking it or bathing with it, or by reciting them over oil and anointing oneself with it. As for what some believe about the specific properties and secrets of each name, or the existence of a spiritual servant for each name, or that each illness has a specific name that cures it, all of this is speaking about Allah without knowledge, and there is no authentic text in the Qur'an or Sunnah (definition) to support it.