Cold & Flu Rescue; Formulated to boost immune health and lessen the severity and duration of cold and flu symptoms.Potent Immune Support; Ester-C®, andrographis, NAC (N-acetyl-L-cysteine), and echinacea work together to support lung, respiratory, and immune health.Fast-Acting & Effective; This antioxidant-rich Ester-C® formula supports immune health during the immune-challenging months of cold and flu season.Well Retained; Clinical studies show that Ester-C® increases vitamin C levels in the body for up to 24 hours.Natural Alternative; Cold & Flu Rescue with Ester-C® is a natural alternative to over-the-counter drugs that simply suppress symptoms.