Does onion water make you feel better? A dietitian's perspective on the viral trend

November 2, 2025 •

4 min read

According to a 2021 review, onions contain at least 25 different flavonoids, including the powerful antioxidant quercetin. With such potent properties, a viral trend has people asking: Does onion water make you feel better? This article examines the scientific evidence behind this popular health claim and separates fact from fiction.

Quick Summary

An examination of the viral onion water trend, exploring its claims for symptom relief, the limited transfer of beneficial compounds into water, and the potential food safety concerns associated with the remedy.

Key Points

Onions Are Nutritious: Whole onions are packed with potent antioxidants like quercetin, vitamins (C, B6), and prebiotic fiber that support immune and digestive health.
Limited Nutrient Extraction: Cold-infusing onions in water does not effectively transfer the most beneficial, fat-soluble compounds like allicin and quercetin into the liquid.
Hydration Is the Main Benefit: The primary provable benefit of drinking onion water when sick is hydration, which helps relieve congestion—a benefit also found in plain water or broth.
Potential Food Safety Risks: If not prepared hygienically and stored properly in the refrigerator, steeped onion water can pose a risk of bacterial contamination.
Opt for Whole Onions: To get the full health benefits, consume whole onions (raw or cooked), as they provide the fiber and nutrients that are largely left behind in infused water.
Placebo Effect Can Influence Perception: Any feeling of improvement after drinking onion water may be influenced by the placebo effect, where the belief in a remedy makes you feel better.

The Viral Trend: Why Onion Water?

Fueled by social media, the practice of soaking sliced onions in water and drinking the infusion has gained popularity as a purported natural remedy for common ailments like colds, flu, and respiratory infections. Proponents of the trend often attribute its effectiveness to the inherent health benefits of onions, which are rich in antioxidants, vitamins, and minerals. The appeal lies in its simplicity and the promise of a quick, natural fix for feeling under the weather. However, a deeper look at the science reveals a more nuanced reality about what this simple concoction can and cannot do.

The Proven Power of Whole Onions

Before addressing the onion water specifically, it's crucial to acknowledge the numerous, well-documented benefits of consuming whole onions as part of a balanced diet. Onions are a nutritional powerhouse, offering compounds that support various bodily functions.

Antioxidants and Anti-inflammatory Properties

Onions are particularly rich in antioxidants, especially quercetin, a flavonoid known for its anti-inflammatory and immune-boosting effects. These antioxidants help combat oxidative stress and defend cells against damage from free radicals. Studies have shown that a diet high in flavonoids, like those found in onions, can help reduce inflammation and lower the risk of chronic diseases.

Immune System Support

The high vitamin C content in onions is vital for a healthy immune system. Vitamin C plays a role in the production of white blood cells, which are essential for fighting off infections. Additionally, the selenium found in onions helps modulate the immune response.

Digestive and Gut Health

Onions contain prebiotic fibers, such as fructooligosaccharides, which serve as food for beneficial gut bacteria. A healthy gut microbiome is linked to improved digestion and has a direct relationship with overall immune function. By supporting good gut health, whole onions contribute positively to your well-being.

The Reality of Onion Water: Limited Benefit

While the health benefits of eating whole onions are clear, the benefits of drinking onion water alone are far more limited. Here's why:

Poor Nutrient Transfer: Many of the most potent compounds in onions, such as quercetin and allicin, are fat-soluble or stored within the fibrous layers of the vegetable. Simple cold-infusion in water does not effectively extract these beneficial components. When you discard the onion, you're essentially throwing away most of the valuable nutrients.
Hydration is Key: The most significant, scientifically sound benefit of drinking onion water is the hydration it provides. Staying well-hydrated is crucial when you are sick, as it helps thin mucus, keeps membranes moist, and aids in overall recovery. This is a benefit you would receive from drinking plain water, broth, or tea.
Placebo Effect: The belief that a remedy will work can sometimes make you feel better, a phenomenon known as the placebo effect. If you expect to feel better after drinking onion water, your brain might register a reduction in symptoms like fatigue or pain, even if the liquid itself had minimal effect.

Potential Risks and Precautions

While generally safe for most, drinking onion water is not without risks, especially if not prepared properly or for those with certain sensitivities.

Food Poisoning: Onions grow underground and can harbor bacteria like E. coli or Salmonella. Soaking raw, unwashed onions in water for extended periods (especially at room temperature) can encourage bacterial growth, posing a risk of foodborne illness. Always wash produce thoroughly and refrigerate any infused water.
Digestive Discomfort: Onions are acidic, and for some individuals, particularly those with conditions like irritable bowel syndrome (IBS) or acid reflux, they can cause digestive issues like bloating, gas, or heartburn. Raw onions are particularly potent in this regard.
Interactions with Medications: Though rare, excessive onion consumption might interfere with blood-clotting medications due to its blood-thinning properties. Consult a healthcare provider if you are on such medication.

Comparison: Whole Onion vs. Onion Water


Feature	Eating Whole Onions	Drinking Onion Water (Cold-Infused)
Nutrient Intake	High, including prebiotic fiber, vitamins, and minerals.	Low, as water-soluble compounds are limited and fat-soluble ones are not extracted.
Fiber Content	Rich source of dietary fiber, supporting gut health.	Almost zero fiber, missing crucial prebiotic benefits.
Antioxidant Absorption	Full absorption of potent antioxidants like quercetin.	Minimal absorption; most is discarded with the onion.
Primary Benefit	A wide range of health benefits, including heart, bone, and immune support.	Primarily hydration, which is essential when sick.
Preparation	Versatile for cooking, maximizing nutrient availability.	Simple, but preparation must be hygienic to avoid contamination.
Flavor	Strong, pungent, or sweet, depending on the variety and preparation.	Mild, onion-y flavor that some find unpleasant.

Making an Informed Choice

When you're not feeling your best, it's easy to be drawn to seemingly magical cures. However, the best approach is often the simplest and most evidence-based. If you enjoy the taste, drinking onion water can serve as a hydrating liquid, but it is not a cure-all. A more effective approach to reaping the benefits of onions is to consume them whole, either raw in salads or cooked in soups and stews. Warm beverages like onion tea (made by boiling onions, sometimes with honey and ginger) can also offer soothing relief for a sore throat or cough.

Conclusion

For those wondering, 'does onion water make you feel better?' the answer is complex. While onions are undeniably healthy, the water-infusion method is largely ineffective for extracting the key beneficial compounds that offer the most potent effects. Any perceived improvement in cold or flu symptoms from drinking onion water is likely due to the crucial role of hydration or the placebo effect, not a unique curative property. For maximum nutritional gain and anti-inflammatory support, it is best to incorporate whole, properly prepared onions into your diet rather than relying on this unproven viral trend. Always prioritize sound medical advice and evidence-based remedies when unwell.

Click here for more information on the bioactive compounds and health functions of onions.

Frequently Asked Questions

No, there is no scientific evidence that onion water can cure or significantly shorten the duration of a cold or flu. The perceived benefits are more likely from hydration and the placebo effect.

No, it is not safe. Leaving infused water with raw vegetables like onions at room temperature can cause harmful bacteria, such as E. coli or Salmonella, to grow. Refrigerate all infused water and discard it within 3 days.

The most effective way is to eat the whole onion, either raw or cooked. This ensures you get all the fiber and potent antioxidant compounds that are not effectively transferred into water.

There is some preliminary research on the use of raw onion juice for insomnia. However, these studies are limited and more research is needed to confirm the effect. Consult a healthcare professional for sleep disorders.

Some individuals may experience digestive problems like gas, bloating, or heartburn, especially if prone to such issues or sensitive to the carbohydrates in onions. Bad breath is another common side effect.

Eating whole onions provides you with all the dietary fiber and a much higher concentration of antioxidants and sulfur compounds, as many of these are not water-soluble and are left behind when you discard the onion.

While generally safe for most, pregnant women, young children, and immunocompromised individuals should be cautious with homemade infused waters due to the risk of bacterial contamination. It is always best to consult a doctor before trying new home remedies.

The high vitamin C content and antioxidants in whole onions support the immune system, but drinking cold-infused water is not an efficient way to get these benefits. Consuming the whole vegetable is a far better option.