If it's pearly white then you're good. If it's yellowish then it's just confirmation that you're sick and your body is fighting something off, wouldn't hurt to up your dosage on vitamins and good health foods. If it's REALLY green then your body is in defcon 5 or possibly losing the fight. The more green your mucus is, the more your body is battling something in your body. White blood cells, after they do their job and die off, are ejected through your nasal passage along with other bacteria. Mucus is the delivery system your body uses so you'll be able to tell exactly what's going on in your body. The more dead white blood cells there are the more discolored your mucus becomes. It's good to know how to do health checks on yourself and make sure your body is in order. Listen to your body. It's one more step to independence and getting away from these modern day medical establishments that want you helpless and dependent.