1. This condition is known as Pica.
2. Craving and chewing ice is also known as Pagophagia.
3. It may be realted to:
a. Iron deficiency anemia
c. Zinc, Calcium or Magnesium deficiency
e. Glossitis (swelling and pain in the tongue, secondary to iron and multi-vitamin deficiency
4. You may discuss this with your doctor to investigate and help treat the cause.
5. There is no harmful effect except ice can cause frequent sore throat
and cold-stimulus headaches.