What Is Ferrous Sulfate in Dog Food?

Ferrous sulfate in your dog's food provides him with the iron he needs.
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That long list of ingredients with serious-sounding names on your dog's food can be confusing. Some of those additives are good for your dog and some aren't so healthy. Fortunately, ferrous sulfate is a vital nutrient and a good thing to see on the label.


Ferrous sulfate is an iron supplement. It's added to all sorts of things, from human foods and supplements to fertilizers, dyes and processed food for pets, including dogs. Ferrous sulfate is also known as iron sulfate and is commonly called green vitriol because of its bright green color in its natural state. It is added to your dog's food to increase the amount of iron he receives.


Just like all animals, dogs need iron in their diet to stay healthy. Iron helps your dog's body produce red blood cells, which are vital for transporting oxygen. Iron is also important for digestion and it strengthens your pup's immune system. While other ingredients in your dog's food, like chicken, beef, lamb or fish, may contain iron, adding ferrous sulfate ensures that your dog gets enough of this important nutrient. Unlike many other dog food additives, ferrous sulfate is a good thing to see on the label.


Dog food with ferrous sulfate is designed to provide nearly all the iron your dog needs in his diet. This means it's important to be careful when adding any supplements to your dog's diet. While iron is necessary, too much of it can be harmful. When combining vitamins or health supplements with your dog's regular diet, make sure he's not getting too much iron. On the other hand, if you are making your own dog food, it might be a good idea to add a supplement that contains ferrous sulfate. It's also important to keep any vitamins or supplements out of your dog's reach so he can't eat too many at once.

Iron Toxicity

The right amount of iron is a good thing, but too much is dangerous. If your dog consumes more iron than his body can process, it can cause damage to his liver, kidneys, heart and stomach. Iron toxicity can happen quickly, like in the case of a dog eating an entire bottle of vitamins, or iron can build up in the body over time if your pooch is regularly receiving too much in his diet. Symptoms of iron toxicity include bloody diarrhea, vomiting and sluggishness. It's important to get medical treatment for your dog right away, even if he seems to be feeling better, since an iron overdose can cause serious damage to his organs.