1. should be easily digestible.
2. No bacterial contamination.
3. Osmolality as the body fluids (about 300 milliosmols/L)
4. Concentration ~ 1 k.cal /1 ml. ( don,t over 1.5 k.cal / 1 ml)
5. Optimal distribution: protein 15-20% fat 25- 30% carbohydrate 50-60%
6. Can flow through NG tube into GI tract.