We love Nature's Way Sambucus Elderberry Syrup for prevention and while sick. And Boiron's Chestal for coughs. We always have Emergen-C and Echinacea tea on hand.
We have found the last couple years that keeping our vitamin D levels good helps a ton. We've been using Carlson D Drops for that. The other thing my husband and I swear by is Lemon Ginger Echinacea juice. Works great, though it is a tough sell to the 6 year old.
We've tried Asian Pear tea and it seems to really help with coughs.
What are your trusted remedies for your kids during cold and flu season?