Fluid loss occurs when the body loses water or any essential fluid, usually because of compromised body mechanisms due to illness or abnormalities. Ideally, the amount of water taken into the body should equal the amount of water lost through natural processes, such as sweating, urination, and defecation. If that is not the case, a fluid imbalance occurs, which alters many functions. Fluid loss causes undesirable symptoms, such as mild headache, fatigue, and illness. At worst, fluid loss will result in death due to the effects of dehydration. Therefore, increased fluid intake is advised. Fluids can be replaced via eating, drinking, and (for infants) breastfeeding. In cases of excessive fluid loss, oral rehydration processes can raise fluid levels.