In the Middle Ages it was not uncommon to write spells of protection around a door jamb— the portal through which the occupants of a house (or barn) came and went. For extra protection to guard against illness as the weather changes and allergy season approaches, write this spell in chalk around the inside of your front door:

To all who come and go from here,
Health and wellbeing shall adhere!
Bring nothing back that carries ill,
So mote it be, this is my will!

Renew the words as needed as the year progresses.