Ferrous sulfate (FeSO4) is widely used in various applications, including:

1. Medicine: Ferrous sulfate is used to treat iron deficiency anemia, a condition where the body does not have enough iron to produce red blood cells.

2. Fertilizer: Ferrous sulfate is used as a soil amendment to provide plants with essential nutrients such as iron, sulfur, and magnesium.

3. Water treatment: Ferrous sulfate is used to remove impurities from water, including hydrogen sulfide, which is responsible for the characteristic rotten egg smell.

4. Animal feed: Ferrous sulfate is added to animal feed to prevent and treat iron deficiency in livestock.

5. Pigment: Ferrous sulfate is used as a pigment in the manufacture of inks, paints, and dyes.

6. Industrial applications: Ferrous sulfate is used in the production of cement, gas purification, and in the manufacturing of other chemicals.