Since then bodily medicine is given to all manner of sick persons, it seems that this sacrament should be given in like manner to all. On the contrary, This sacrament is called by all Extreme Unction. Therefore this sacrament should not be given in every case of sickness. I answer that, This sacrament is the last remedy that the Church can give, since it is an immediate preparation for glory. Therefore it ought to be given to those only, who are so sick as to be in a state of departure from this life, through their sickness being of such a nature as to cause death, the danger of which is to be feared.
Any sickness can cause death, if it be aggravated.
But if we consider the degree and the stage of the complaint, this sacrament should not be given to every sick person. But the principal effect of this sacrament is that immunity from disorder which is needed by those who are taking their departure from this life and setting out for the life of glory. Hence the comparison fails. For these diseases are full of danger and cause death quickly. Now when there is danger it is the time to apply the remedy.