E-C-H-I-N-A-C-E-A
Long ago, I used to get wicked head colds or flus, followed by miserable bronchial coughs. This combination lasted two or three weeks, and occurred four or five times annually. Then Echinacea came along, and I only have one, if any each year, and it is very short lived.
The trick with Echinacea is to have it handy, and take it at the first hint of a cold. I just finished one, and it lasted a mere three days. I don't expect another one till next year. Apparently it gives the immune system a boost; its benefits were discovered long ago by the Plains Indians. Whatever, it works for me!