Olives provide many health benefits. They help eliminate excess cholesterol from the blood and control blood pressure. Olives are a good source of dietary fiber and vitamin E. They act as antioxidants, protecting cells, veins, and cavities. Olives can reduce the effects of degenerative diseases like Alzheimer's and tumors. However, for some people with low blood pressure, olives may cause dizziness due to their blood pressure lowering effects. Very strong olives can also cause stomach irritation or diarrhea in rare cases.