Echinacea is a herb derived from a common plant in the daisy family called cone flowers. The tall, purple/pink spikey ones found in prairies and woods. Echinacea boosts the immune system which is why it's so popular in dealing with colds and flu. However those with auto immune problems should avoid using it.
I tried the echinacea tea and it needed like a ton of honey in it to make it taste good, that's the only kind i can think of