04 Nasal Irrigation

🫧 The Underrated Cold Remedy

Nasal saline irrigation is the one home intervention with real evidence for shortening your cold — here's how it works and how to do it safely

Matt Bezzant, MD · April 1, 2026 · 7 min read

Most OTC cold remedies make you more comfortable while your immune system does the work. Nasal saline irrigation is different — it's the one widely available home intervention with clinical evidence for actually reducing how long your cold lasts. It's also inexpensive, has minimal side effects, and can be made at home.

Why it works — the mechanism

When a cold virus infects your nasal passages, it binds to the surface of the cells lining your nose and begins replicating. The resulting immune response floods the area with fluid and inflammatory cells. Nasal irrigation works through several complementary mechanisms.

First, it physically flushes viral particles, mucus, and inflammatory debris out of the nasal passages (mechanical clearance). Second, hypertonic saline — a saltier solution than your body fluids — draws excess fluid out of the swollen nasal lining through osmosis (osmotic dehydration of the mucosa), directly reducing swelling. Third, regular flushing supports the microscopic hair-like structures that line your airways (cilia), which move mucus and debris toward the throat to be cleared. Viral infections impair ciliary function; saline irrigation helps compensate for this.

What the evidence actually shows

~2 days

Shorter illness duration compared to no irrigation

36%

Reduction in use of OTC cold medications

35%

Reduction in transmission to household members

🔍 The Evidence

A well-designed RCT found that hypertonic saline nasal irrigation and gargling, started early in a cold, shortened illness by approximately 2 days, reduced OTC medication use by 36%, and reduced household transmission by 35%. A meta-analysis comparing hypertonic to isotonic saline found hypertonic solution superior for symptom improvement, with the greatest benefits seen with higher concentrations (3–5%) and high-volume devices.

My Synthesis

Two fewer days of cold symptoms is a clinically meaningful benefit. And the 35% reduction in household transmission is one of the most underappreciated numbers in this literature. If you live with children, elderly family members, or immunocompromised individuals, that number alone makes irrigation worth doing. The evidence is stronger for hypertonic saline than isotonic, and for high-volume devices than simple sprays.

Isotonic vs. hypertonic saline — which to use

Isotonic saline

~0.9% salt

¼ tsp non-iodized salt per 1 cup water

Same concentration as your body fluids. Gentler, causes less burning. A reasonable starting point for beginners or sensitive nasal passages — but the evidence for symptom reduction is less robust than for hypertonic.

Hypertonic saline — Preferred

~2–3.5% salt

½ to ¾ tsp non-iodized salt per 1 cup water

Higher salt concentration than body fluids. Works through both mechanical flushing and osmotic reduction of nasal swelling. More effective for symptom improvement and illness duration — but can cause temporary burning, especially at first.

My Recommendation

I recommend starting with hypertonic saline if you can tolerate it — the evidence supports meaningfully better outcomes. If the burning is uncomfortable, start with isotonic and gradually increase the salt concentration over a few days. Adding ¼ tsp of baking soda to either solution buffers the pH and reduces irritation noticeably.

How to make your own solution

Use non-iodized salt — pickling or canning salt works well. Iodized table salt can irritate the nasal passages.

Isotonic Saline

1 cup (240 mL) safe water (see water safety below)
¼ tsp non-iodized salt
¼ tsp baking soda (optional — reduces irritation)

Hypertonic Saline — Recommended

1 cup (240 mL) safe water (see water safety below)
½ to ¾ tsp non-iodized salt
¼ tsp baking soda (optional — reduces irritation)

Mix until completely dissolved. Make a fresh batch daily — do not store solution for more than 24 hours.

Water safety — this is not optional

⚠ Never use unfiltered tap water

Tap water can contain Naegleria fowleri, a rare amoeba that causes primary amoebic meningoencephalitis (PAM) — a brain infection that is almost universally fatal. Cases linked to tap water nasal irrigation have been reported to the CDC. The FDA and CDC are unambiguous: do not use unfiltered tap water for nasal irrigation.

Use only: distilled or sterile water (available at pharmacies), boiled tap water (boil 1–5 minutes, cool before use), or filtered water through a filter labeled NSF 53 or NSF 58.

How to do it — step by step

Use a neti pot, squeeze bottle, or bulb syringe. Clinical guidelines recommend a high-volume device — approximately 240 mL (8 oz) per side — because high-volume irrigation is significantly more effective than simple saline sprays.

Wash your hands thoroughly before handling your device or solution.
Fill your device with prepared saline solution at a comfortable temperature — slightly warm is easiest to tolerate.
Lean over a sink and tilt your head to one side so one nostril is higher than the other.
Pour or squeeze the solution into the upper nostril. Breathe through your mouth.
Let the solution drain out of the lower nostril — or out of your mouth if it flows that way. Both are normal.
Gently blow your nose to clear remaining solution, then repeat on the other side.
After each use, rinse your device with distilled or boiled water, then let it air dry completely.

See it in action

If the written steps feel abstract, watching a demonstration first makes the technique much easier to replicate — especially the head positioning, which is the part most people get wrong on the first try.

Neti pot technique demonstration. Key points: tilt your head fully to the side, breathe through your mouth, and don't force the flow — gravity does the work.

A note on first-time use

It looks stranger than it feels. Most patients who try it are surprised by how comfortable it is once the technique clicks — usually by the second or third attempt. The most common first-try mistake is not tilting the head far enough, which causes solution to run down the throat instead of out the lower nostril.

What about gargling?

The same hypertonic saline solution can be used for gargling. The clinical trial showing the 2-day reduction in illness duration included both nasal irrigation and gargling as part of the intervention. Gargling helps by clearing viral particles from the throat and posterior nasal passages that flushing alone doesn't fully reach. If you have a sore throat, it also provides direct symptom relief. I recommend doing both.

Sources: Achilles N, Mösges R. Nasal saline irrigations for the symptoms of acute and chronic rhinosinusitis. Curr Allergy Asthma Rep. 2013 · Kanjanawasee D et al. Hypertonic vs isotonic saline nasal irrigation: systematic review and meta-analysis. Am J Rhinol Allergy. 2018 · Ordemann AG et al. Can contaminated water be rendered safe for nasal saline irrigations? Laryngoscope. 2017 · Payne SC et al. Clinical Practice Guideline: Adult Sinusitis Update. Otolaryngology–Head and Neck Surgery. 2025.

More in this series
Part 01: What Is the Common Cold? · Part 02: High-Risk Situations · Part 03: OTC Medications · Part 04: Nasal Irrigation (you are here) · Part 05: When to See a Doctor

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