Hi Thanks for trusting healthcaremagic for your health issues. I understand your concern. Anemic patients feels palpitation often because of reflex sympathetic stimulation, So it s not iron toxicity. However lose stool are due to ferrous fumarate. It can cause diarrhea or constipation varying person to person. For that you start Oral Rehydration Solution (WHO approved) to prevent water and electrolyte loss. Take ferrous fumarate tablet after meal only. usually iron tablets are continued 1 month after hemoglobin level comes to normal range to replenish iron store of your body which is depleted in anaemia. Along with iron rich food can be taken. Non-veg - meat. Vegetarian - dry fruits, jaggery, green leafy veg. etc... regards Dr. hiren