Holy water, like all sacramentals, has long been part of the daily lives of Catholics. In this time of special health concerns, it is good to be reminded of one of the traditional beneficial effects attributed to the use of holy water. The following passage is from the book Holy Water and Its Significance for Catholics, by Rev. Henry Theiler.
As we learn from these same prayers of the Church, holy water is a special remedy against ills of the body. This effect is contained in the second prayer pronounced over the water. Therein the Church thus addresses herself to God:
"Graciously give ear when we call upon Thee, and pour upon this element . . . the power of Thy blessing; let Thy creature [water] . . . by divine grace be effectual for driving away diseases, that on whatsoever in the houses or places of the faithful this water shall be sprinkled, it may be freed from all uncleanness and be delivered from hurt."
From these words it is plain that holy water is not only a means to drive away sickness
but is likewise a protection against sickness.
The graces of sacramentals should not be confused with anything magical; they are derived from and conferred by Our Savior.
"For well-disposed members of the faithful, the liturgy of the sacraments and sacramentals sanctifies almost every event of their lives with the divine grace which flows from the Paschal mystery of the Passion, Death, and Resurrection of Christ. From this source all sacraments and sacramentals draw their power." ( #1670 Catechism of the Catholic Church)
Every Catholic household should have its own supply of holy water, blessed salt, blessed oil and blessed candles. Consider it a form of Catholic prepping!