I would suggest 2 key herbs that can help do that: Elderberry Echinacea I like to steep a bit of both for a warm herbal tea, and I often add peppermint herb for a yummy mint flavor.
For another immune boosting option that is super convenient, try these cold care capsules from Rosemary’s book. These 4 powdered herbs come together in a vegetable or gelatin capsule, to pack an amazing immune boosting punch.