The invention is directed to ginseng fractions and methods for activating innate and adaptive immune responses to prevent, treat or ameliorate a condition in a subject by administering to the subject an effective amount of a ginseng traction, a pharmaceutical composition comprising the fraction in combination with another medicament or with one or more pharmaceutically acceptable carriers, or a food item comprising the fraction. The fraction may be made from Panax quinquefolius' or may be selected from CVT-E002, PQ2, PQ223 and purified fractions from CVT-E002, PQ2 and PQ223.