Nausea, heartburn, and stomach discomfort are frequent adverse effects of ferrous sulfate usage. Iron supplements may also interfere with some drugs, such as antacids and proton pump inhibitors. Large amounts of iron can be toxic to the body. Iron is needed for healthy blood formation and for many other functions within the body. However, too much iron can be just as harmful as not enough. Excessive iron intake can lead to oxidative stress and inflammation. This can increase your risk of developing diseases such as cancer, diabetes, and cardiovascular problems. The best way to ensure you are getting an adequate amount of iron is through food alone. Foods high in iron include meat, fish, eggs, dried fruits, and dark-colored vegetables. Smaller amounts of iron can be found in beans, peas, lentils, potatoes, spinach, and broccoli. Iron supplements are useful for people who need extra help with nutrition or who have certain medical conditions that affect their ability to absorb nutrients from food. Taking supplements is only necessary if you do not get enough iron through food alone. If you take medications or supplement with vitamins D and C at the same time as iron, then this should be done separately from foods so as not to exceed recommended doses.