OPC Antioxidant Reference Guide 

OPC Side Effects

OPC Side Effects Because the Food and Drug Administration do not regulate herbal remedies or antioxidant supplements, it is important to research side effects that may be caused by OPCs. However, there are little or no known side effects associated with OPCs. In rare cases, OPC side effects that have been reported cause an upset stomach and our experience indicated that they are best taken with meals. NOTE: Some people may be allergic to grape seed extract, pine bark extract or other substances found within OPC's. If you experience and breathing problems including(tightness in your chest or chest pain) or if you develop skin hives or itchy/swollen skin, stop taking your OPC Antioxidant immediately and consult your doctor.The OPC may be causing these symptoms which suggests that you are allergic to it. Breathing problems or tightness in your throat or chest Chest pain Skin hives, rash, or itchy or swollen skin