I took 10 fl of magnesium citrate for constipation and its not working .does eating food and consuming lots of water make "it" go ?

Yes ....: Generous (64+ ounces daily) water and fluid intake is your best strategy to deal with constipation. Including high fiber foods to promote efficient transit through the bowel is also helpful: whole grain cereals, bread, brown rice, vegetables and fruit. A third strategy is daily physical activity such as 30-45 minutes of brisk walking. Put those together, and you should see some results!