You can make a basic mouth rinse from toothpaste by mixing a small amount with water, but the result won’t match a commercial mouthwash in effectiveness or comfort. Toothpaste and mouthwash share many of the same ingredients, with one key difference: toothpaste contains abrasives designed to scrub teeth with a brush, and those gritty particles serve no purpose in a rinse. Understanding what you’re actually getting from a toothpaste rinse helps you decide whether it’s worth the effort.
The Simple Method
Squeeze about a pea-sized amount of toothpaste into a cup, add roughly two tablespoons (30 ml) of warm water, and stir until the paste dissolves as much as it will. Warm water helps break up the paste faster. You’ll end up with a cloudy, slightly gritty liquid. Swish it around your mouth for 30 to 60 seconds and spit it out.
The mixture won’t fully dissolve. Toothpaste contains fine abrasive particles, typically silica or calcium carbonate, that are meant to polish tooth surfaces during brushing. In a rinse, those particles just settle to the bottom of the cup or float around your mouth without doing much. Commercial mouthwashes have essentially the same composition as toothpaste minus these abrasives, which is precisely why they exist as a separate product.
What You Actually Get From It
A toothpaste slurry provides a burst of minty freshness and delivers some fluoride to your teeth. Standard toothpaste contains 1,000 to 1,200 ppm of fluoride. When you dilute it in water, that concentration drops significantly. For comparison, commercial fluoride rinses typically contain 100 to 230 ppm for daily use, or 900 ppm for weekly or biweekly use. Depending on how much toothpaste you use and how much water you add, your DIY rinse could land somewhere in this range, but the concentration is hard to control precisely.
Where a toothpaste rinse falls short is killing bacteria. A 1992 study comparing plaque regrowth over five days found that a toothpaste slurry performed no better than plain salt water at preventing plaque buildup. Both were significantly outperformed by antiseptic rinses containing chlorhexidine. So if you’re hoping for germ-killing power, a toothpaste rinse won’t deliver it. The antibacterial agents in commercial mouthwash are specifically formulated to stay active in liquid form at the right concentration.
Potential Irritation Concerns
Most toothpastes contain sodium lauryl sulfate (SLS), a foaming and cleaning agent. SLS has been linked to increased mouth irritation in people prone to canker sores. The good news is that research shows about 96 to 97% of SLS clears from the mouth within two minutes of rinsing, so contact time is brief. Still, if you get canker sores frequently, swishing a toothpaste solution may trigger discomfort. In that case, look for an SLS-free toothpaste if you want to try this, or simply skip it.
The abrasive particles are another consideration. While they’re too fine to cause damage during normal brushing (typically 20 micrometers or smaller), swishing gritty water around your mouth is unpleasant. It won’t harm your teeth or gums in a single use, but it’s not a smooth rinsing experience either.
When This Makes Sense
A toothpaste rinse is a reasonable pinch-hitter in specific situations: you’re traveling and forgot your mouthwash, you’re camping with limited supplies, or you simply want a quick freshening rinse and toothpaste is all you have. For temporary fresh breath, it works fine. The mint flavoring in toothpaste is the same type used in commercial rinses, and it masks odors effectively for a short time.
It does not make sense as a long-term replacement for commercial mouthwash. If your goal is reducing bacteria, preventing gum disease, or getting a therapeutic fluoride rinse, a product designed for that purpose will outperform a toothpaste slurry every time. Over-the-counter fluoride rinses deliver a precise, consistent fluoride concentration and contain antimicrobial ingredients formulated to work in liquid form. A toothpaste-water mix gives you unpredictable fluoride levels and no meaningful antibacterial effect beyond what plain water provides.
A Better DIY Alternative
If you want a simple homemade rinse, warm salt water (half a teaspoon of salt in a cup of water) performs just as well as a toothpaste slurry for temporary freshness and has the added benefit of being smooth, easy to make, and slightly soothing to irritated gums. It won’t deliver fluoride, but neither will a toothpaste rinse in any reliable dose. For fluoride protection, brushing with toothpaste twice a day is far more effective than any rinse you could make from it.