Yes. Some antioxidants are water soluble and will just leave the body through the urine however some are fat soluble and too much of these can be harmful. Too much vitamin c and magnesium can cause loose bowels but are not dangerous unless you keep taking them and become dehydrated.
Yes, VitE & beta crt. Although dietary and reasonable supplement intake of anti-oxidants is a good thing for your health, too much can be a problem. Cleveland Clinic researchers published a study recently showing that excess beta carotene can actually increase risk for cardiovascular disease. Other studies have shown a link with increase cancer. Vit E also can be excessive & cause bleeding.