In industrial applications, ferrous sulfate is used as a reducing agent and colorant. Ferrous sulfate is on the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system. Together with other iron compounds, ferrous sulfate is used to fortify foods and to treat and prevent iron deficiency anemia. Constipation is a frequent and uncomfortable side effect associated with the administration of oral iron supplements. Stool softeners often are prescribed to prevent constipation.