Correct, this is one of the most frequent charms found in medieval Europe. Against the falling sickness, something involving variations of the names Caspar, Melchior, Balthasar is to be written on a note to be worn around the neck. An example from Katherine Hindley's book:
British Library, Sloane Ms 1314, fol. 38v (ca. 1350– 1400)
For þe fallyng euyl. Take þe blod of þe litel fynger of þe ryht hande
of hym is seke ⁊ wryte þese thre names in parchemyn with þe blod
+ Jasper + Melchior + balthazar + ⁊ let close hit ⁊ heng hit aboute
his nek þat is seke [...]
British Library, Sloane Ms 1314, fol. 38v (ca. 1350– 1400)
For þe fallyng euyl. Take þe blod of þe litel fynger of þe ryht hande
of hym is seke ⁊ wryte þese thre names in parchemyn with þe blod
+ Jasper + Melchior + balthazar + ⁊ let close hit ⁊ heng hit aboute
his nek þat is seke [...]