From his blog:
[from "Be-Ahavah U-Be-Emunah" – Parashat Shoftim 5769 – translated by R. Blumberg]People often times turn to Rabbis asking for "segulot" [spiritual aids or shortcuts] to help the sick. Besides going to the doctor, they look for spiritual tricks, recitation of a particular verse, or an amulet, just so there is some change for the better. Unfortunately, they are searching in vain for something that does not exist.Some will respond: “Who says? My aunt had no children, she used a 'segulah' and now, thank G-d, there are children around her table.” Yet someone else had a childless aunt who used no "segulah," and children were born to her anyway. [...]Is it written that when our great Sages had troubles, they used "segulot," with mezuzot and amulets? Where have we heard of such a thing? Not in the Torah, not in the Mishnah and not in the Talmud. Rather, they prayed and they repented and performed kind deeds.