I feel glad to share this information with you. This blog will help us to reach out to people and also reminds us of our duty in the society. Hope each of you will make best of this information. This information is taken from USP DI, Volume II, Advice to the patient 
Information for the pharmacist:
1. Iron supplements are chelated by acetohydroxauric acid; this may result in reduced intestinal absorption of iron.
2. Concurrent use of alcohol with ferric iron for a prolonged period may result in toxicity since absorption and hepatic storage of iron is increased, especially if alcohol usage is high.
3. Concurrent use of any of the following with iron will decrease iron absorption because of the formation of less soluble or insoluble complexes. Antacid containing carbonates or magnesium tricilicate or coffee or eggs or foods or medication containing bicarbonates, carbonates , oxalates or phosphates or milk or milk products or tea (containing tannic acid) or whole grain breads and cereals (containing phytic acid) and dietary fiber. Iron supplements should not be used within 1 hour before or 2 hours after ingestion of any of the above.
4. Concurrent use of iron supplements with pancreatic or pancrelipase may decrease iron absorption with, pencillamine may decrease the effects of pencillamine, with tetracyclines oral may decrease absorption of tetracycline. Vitamin E impair the hematologic response in patients with iron deficiency anemia.
Information to the patient:
1. Iron is used by your body to make red blood cells.
2. The best way to take oral iron is to take it on an empty stomach, 1 hour before or 2 hours after meals. But if you suffer from stomach upset it may be taken with the food.
3. Take iron with water or fruit juice, a full glass (240ml) for adults, half glass (120 ml) for children, to prevent staining of teeth and to mask taste.
4. Keep iron medications out of reach of children. Overdose is especially dangerous in young children.
5. Oral iron supplements may make your stools a very dark or black colour. This is not usually of any concern.
6. Oral iron supplements may sometimes cause diarrhea or constipation. If this is persistent or troublesome, tell your doctor.
Advice for the patient: Drug information in lay language; USP DI; 1995 15th Edition page nos: 988-989.