Astragalus
Astragalus membranaceus or milk vetch has been used in Chinese medicine for over 2,000 years to strengthen the immune and respiratory systems and to fight the flu. Astragalus belongs to a class of herbs called adaptogens, and helps the body handle stress. Astragalus also fights pathogens like bacteria and viruses.
Dosage: one dropper of tincture of Astragalus (standardized to 15 percent polysaccharides) to a hot liquid like tea or soup three times a day. As tablets, take 350 to 400 milligrams three times a day.

Ginseng can have great effects on your health!

Zinc: Zinc inhibits the reproduction of rhinovirus, and has been found to be especially good for treating viral sore throats. A recent study on the effectiveness of zinc showed that taking a zinc lozenge every 2-3 hours, shortened the duration of cold symptoms. Overdosing with zinc can have side effects, such as an effect on the uptake of iron.
Dosage: one lozenge every 2-3 hours for duration of the cold or flu. Keep in the mouth for 5-10 minutes. Or 30 to 50 milligrams a day.

 

Echinacea: Echinacea has powerful antiviral and immunity-boosting effects. It is used to rev up the immune system at the first sign of a cold. Echinacea has been found to work better before you get sick, to build up immunity. It has not been found as effective for treating a cold or flu.
Dosage: take daily according to manufacturers instructions. Take daily during the fall and winter months.