Ferrous sulfate 325 milligrams is an iron supplement used to treat iron deficiency anemia, according to Everyday Health, Inc. It is sometimes prescribed by a doctor for other purposes.
Drugs.com states that some people need to consult their doctors before using this supplement, including people who suffer from alcoholism, people who receive regular blood transfusions, and people who have iron-related illnesses, such as iron overload syndrome, hemolytic anemia, porphyria and thalassemia. Ferrous sulfate is not to be given to a child unless specifically directed by a doctor. Everyday Health, Inc. recommends taking ferrous sulfate on an empty stomach with a full glass of water and recommends against taking other medications, vitamins or minerals within two hours of ferrous sulfate.