When suffering from the cold, what are the health effects of (instead of clearing the nose itself) sucking the mucus in the nose into the mouth internally and then spitting it out?

You are disturbing your natural breathing anatomy. Do not try to suck mucus from your blocked nose to throat. It will lead to DNS (deviated nasal septum).

Although mucus kills germs, you should be spitting it out when having cold, instead of swallowing. Nothing will happen except that your cold might not go too soon in some cases.

If you still want to suck, do not suck your mucus with pressure from your nose to throat. Be gentle, be patient.

Gently blow your nose, always blow both your nose, even if one is blocked. Never ever use force or pressure. BE GENTLE, be patient, I know its irritating. But trust me or else later you will repent.

Try Nasya - Shadbindu Tel to relieve from blocked nose. Preferably do it everyday. After all prevention is better than cold, oops i meant cure. Read on Nasya, why people used to do Nasya, you will know what I am talking about.

So read my other answers if your sinus, cold, respiratory issue is chronic or has been there for more than six months for a holistic solution.

Off late i also found something called Salt room therapy. While relaxing in one of treatment rooms, customers inhale the dry, salt-enriched air deep down into the lungs, where the healing benefits do their greatest healing. The salt loosens the mucus, which begins to clear quickly, and inflammation is reduced, which makes more room in the airways for you to breathe. Symptoms subside, sometimes for up to 12 months.

Dry salt air is more powerful than moist air. The negatively charged ions in salt improve our health and mood. Inhaling particles may reduce inflammation and mucus in the lungs, improving most respiratory conditions such as asthma, allergies, bronchitis, sinus congestion and Chronic Obstructive Pulmonary Disease (COPD).

See if you have it nearby or see if you can customize, like use a nebulizer at home. BUT MAKE SURE YOU KNOW HOW TO PREPARE THE RIGHT SALT WATER OR SALINE SOLUTION. PLUS ENSURE ITS HYGENIC AND YOU HAVE CONSULTED A DOCTOR WHILE CUSTOMIZING YOUR SALT ROOM THERAPY USING A NEBULIZER AT HOME.