Feosol® Original contains a form of iron called ferrous sulfate which may produce side effects such as constipation, diarrhea, stomach cramps or upset stomach. One more iron side effect is dark or black stool. Do not be alarmed if taking iron causes your stools to turn black; this is a typical side effect due to unabsorbed iron in the intestines.
If you are experiencing any of these effects and they persist or worsen, contact your doctor or pharmacist. In some cases, people may experience local throat pain and heartburn due to possible contact irritation from the iron.
In addition to Feosol Original with ferrous sulfate, Feosol offers two gentler iron options: Feosol® Natural Release, an iron supplement for which the absorption is naturally regulated by your body; and Feosol® Complete, a dual-iron formula which maximizes iron absorption while minimizing side effects.