Propolis, (the plaster of sorts of the bee hive)makes a fabulous immune booster. Look for a local product (Bee Kind in Sebastopol) for the purpose of our pollens and your histamine reactions.
There are a variety of natural immune boosters out there in our food supply. It just really depends on what you believe is working for your particular needs.
From herbs to bee products to food, so many choices with no one answer being the right one.