As with everything we eat, side effects are possible. C500 contains only FDA approved ingredients that are used to provide you with natural nutrients and enhance your body's natural processes. Therefore, unwanted side effects are rare. However, everyone is unique and will react differently to different foods. This is why you should consult with your physician before trying anything new and avoid using Sunset when pregnant or nursing. Quercetin is a powerful antihistamine and anti-inflammatory that neutralizes facial and upper body flush zones