Saline solution is a simple mix of salt and water used to rinse nasal passages, clean wounds, flush eyes, and loosen mucus in the lungs. The standard concentration, called normal saline, is 0.9% salt, which means 9 grams of salt per liter of water. That concentration matches the salt level in your body’s own fluids, so it won’t sting or damage tissue. How you use saline depends entirely on what you’re using it for, and each application has specific steps worth getting right.
Making Saline at Home
You can buy pre-made sterile saline at any pharmacy, but making it yourself is straightforward. Dissolve 9 grams of non-iodized salt (roughly one level teaspoon) into one liter of water. The water source matters more than you might think. For nasal rinsing or any use where saline contacts mucous membranes, you need to start with distilled water, store-bought sterile water, or tap water that has been boiled and fully cooled. Tap water straight from the faucet can harbor a rare but dangerous amoeba called Naegleria fowleri, which can cause a fatal brain infection if it enters the nasal passages.
To boil tap water safely, bring it to a rolling boil for one full minute. If you live at elevations above 6,500 feet, boil for three minutes instead. Let it cool completely before mixing in salt. Store any unused boiled water in a clean, covered container. If boiling isn’t an option, you can disinfect water with unscented liquid household chlorine bleach: add the recommended drops for your volume of water, stir well, and let it stand for at least 30 minutes before use.
Homemade saline doesn’t stay sterile for long. Use it within 24 hours of making it, and discard anything that looks cloudy or discolored.
Nasal Rinsing
Saline nasal rinses clear out mucus, allergens, and irritants from the sinuses. You can use a squeeze bottle, a neti pot, or a bulb syringe. Fill your device with the prepared saline at a comfortable lukewarm temperature. Lean over a sink and tilt your head to one side at about a 45-degree angle. Pour or squeeze the saline gently into your upper nostril and let it drain out through the lower nostril. Breathe through your mouth the entire time. Repeat on the other side.
Most adults use about 120 to 240 milliliters (4 to 8 ounces) per session, split between both nostrils. You can rinse once or twice a day when you’re congested. After each use, rinse your device with safe water (distilled or previously boiled) and let it air dry completely. Never share nasal rinse devices between people.
Saline for Babies
Saline drops are safe for infants and are the go-to option when a baby’s blocked nose is interfering with feeding. Place two or three drops into one nostril, then use a bulb syringe or nasal aspirator to gently suction out the loosened mucus. Time it just before a feed so the baby can breathe more easily while nursing or bottle-feeding. Only use saline drops when the baby’s nose is actually blocked. Using them too frequently can irritate the delicate skin around the nostrils, leaving it red and sore.
Cleaning Wounds
Rinsing a minor cut or scrape with saline removes dirt, debris, and bacteria without damaging healing tissue the way soap or hydrogen peroxide can. For a small wound at home, pour or squirt saline steadily across the cut. The goal is gentle pressure, enough to flush out particles but not so forceful that it drives debris deeper. A clean squeeze bottle works well for this. If you have a syringe (without a needle), filling it and pressing the plunger with steady force creates a more directed stream.
Clinical guidelines recommend roughly 30 to 100 milliliters of fluid per centimeter of wound length, depending on how dirty the wound is. For a clean, shallow cut at home, a thorough rinse of a few tablespoons is usually sufficient. Pat the area dry with a clean cloth afterward and cover it with an appropriate bandage.
Eye Rinsing
If something gets in your eye, like dust, a small particle, or a splash of a mild irritant, a sterile saline rinse can flush it out. Tilt your head so the affected eye is lower, then pour or drip sterile saline across the open eye from the inner corner outward. You can also hold your eye open under a gentle stream of clean water from a faucet.
One important distinction: sterile saline is not the same thing as contact lens solution. Contact lens solutions contain disinfecting chemicals like hydrogen peroxide, surfactants, and preservatives such as chlorhexidine. These ingredients are designed to clean lenses, not your eyes. Putting contact lens solution directly into your eyes can cause irritation or, in some cases, chemical burns. If you wear contacts and want to rinse them before inserting, plain sterile saline is fine for that. But for cleaning and storing lenses overnight, you need the disinfecting solution your lens brand recommends.
Nebulized Saline for Respiratory Conditions
Saline can also be inhaled as a fine mist through a nebulizer to help loosen thick mucus in the lungs. This is commonly used by people with cystic fibrosis or bronchiectasis. The concentration for nebulized saline is higher than normal: hypertonic saline with 3% to 7% salt. The higher salt concentration draws water into the airways, thinning the mucus so it’s easier to cough up. The most commonly studied regimen is 7% hypertonic saline inhaled twice daily through an ultrasonic nebulizer.
This is a prescribed therapy, not something to improvise at home. The concentration, nebulizer type, and treatment schedule all need to match your specific condition. Normal 0.9% saline is also sometimes nebulized as a simple moisturizer for irritated airways, but hypertonic concentrations are the ones that actively help clear mucus.
Storage and Shelf Life
Unopened, commercially packaged sterile saline lasts until the expiration date printed on the container. Once you open it, the clock starts ticking. If the sterile seal is broken cleanly and you keep the opening as uncontaminated as possible, use the remaining solution within 24 hours. Discard it immediately if you notice any cloudiness, particles, or discoloration. Homemade saline should be treated even more conservatively: make a fresh batch each day and throw away what you don’t use.
Store opened bottles at room temperature in a clean area, with the cap tightly closed between uses. Don’t let the tip of the container touch your skin, a wound, or the inside of your nose, as this introduces bacteria into the remaining solution.