Some medications should be taken on an empty stomach. This is usually because food prevents the medication from being fully absorbed into the body.
If you are not sure whether you should eat before taking your medicine, check with your pharmacist. If your medication needs to be taken on an empty stomach, take it one hour before meals or two hours after food with a full glass of liquid, usually water. Some medications that should not be taken with food should also not be taken with milk. Check with the pharmacist to see if this is true for your medication.