Recently a coworker of mine introduced me to Astragalus and honestly there's no better herb to cover with the weather being as bleak as it has been. Astragalus is known for promoting healing in conjunction with other herbs as well as increasing the body's resistance to disease in general. If you're wary of a winter illness, it's time to invest in some Astragalus.
Astragalus or Huang Qi has been a key element of Traditional Chinese Medicine for hundreds and hundreds of years.
There's scientific evidence to prove that it works in the bone marrow to produce white blood cells and antibodies. Overall, it greatly improves immune function. But this isn't a one and done type of herb--it takes time to settle into your body. So make sure to take it every day over a period of time if you want to see results.
The way I took it, when my coworker offered me some, was as a powdered root mixed in hot water. It has a sort of sand-colored, murky look to it, but the taste is pleasant! My coworker described it as a hay-like flavor and it reminded me a lot of barley tea--which I found comforting and familiar. Mix it with a little honey and it can make a great addition to your morning herbal supplements.