Can white radish and honey stop coughing? How to make daikon radish, its sugar content, and safety precautions.

When a cough is difficult to relieve, seeing a doctor often only results in the advice to "rest more," which is truly frustrating. A common household dish, white radish with honey, is indeed a long-standing family recipe in Japan, locally called "daikon jasmine" (white radish candy). It only requires two ingredients and can be made at home.

But to use this method with peace of mind, there are a few things worth clarifying first: what does the white radish itself provide, where does the evidence for honey's cough-relieving properties lie in current guidelines, what is the main benefit of drinking this cup, and—Infants under one year old should absolutely not drink this.。

1. What is a cough? First, distinguish between acute and chronic cough.

Coughing is a protective reflex of the body: when the throat or airway is stimulated, nerves send a message to the brain, and then the chest and abdominal muscles expel air to drive away the irritant. Occasional coughing is normal and is not a disease in itself.

Clinically, the first thing to consider is how long it lasts:

Most acute coughs are caused by viral infections, such as the common cold or influenza. The UK NICE guidelines for acute coughs state that these types of coughs belong to...Self-reliefIn such cases, symptoms usually subside within 3 to 4 weeks, so the focus of treatment is on relieving discomfort rather than using antibiotics.

This dividing line is crucial because it determines where "drinking a cup of honey and white radish syrup" should be placed in the overall process—it isOne of the options for symptom reliefThis is neither a way to find the cause nor a method to treat the cause. There are many causes of coughing; a cold is just one of them. Others may include sinus problems, asthma, acid reflux, and lung conditions that require a doctor's evaluation; see this section for more information.Is my cough just a result of a cold?。

II. What are the nutritional benefits of white radish?

In Japan, daikon radish is called "daikon," while in Chinese households it's often referred to as "commoner's ginseng"—this is a colloquial term, not a nutritional classification. According to data from the USDA Food Database, the composition of 100 grams of raw daikon radish is as follows:

Two points are worth noting:

• It contains over 90% water and is extremely low in calories.When you have a dry throat and a painful cough, a cup of water-diluted, sweet-tasting drink can be very soothing, and white radish is the source of both moisture and sweetness.
• It has a high vitamin C content.It contains 22 mg per 100 grams, significantly higher than apples (about 4.6 mg) and watermelons (about 8.1 mg). When eaten raw, white radish is a fairly good source of vitamin C—which is why this method is better with raw radish than cooked radish.

III. How does Traditional Chinese Medicine view white radish stewed with rock sugar?

The following is a description from the theoretical system of Traditional Chinese Medicine, which is a different framework from modern nutrition. The two can be read together, but they are not the same thing.

In its document "Traditional Chinese Medicine Dietary Therapy – Grains and Vegetables," the Office of Chinese Medicine Regulation of the Hong Kong Department of Health lists radish as a vegetable, stating: "White radish is sweet and cool in nature. It can clear heat and generate fluids, resolve phlegm and stop coughing, and aid digestion." The same document also explains the framework of "four qi and five flavors" in Traditional Chinese Medicine: cold, cool, warm, and hot are the four qi; those with mild properties are called neutral; pungent foods have the effect of regulating qi and blood, and dispersing exterior pathogens. White radish has a slightly spicy taste, which is why it is classified in this category.

The common dish "stewed white radish with rock sugar" follows the same line of thought. The official document mentions pears in the fruit section, stating that "those with dry cough can stew them with rock sugar to relieve dry cough"—meaning that in traditional Chinese medicine theory, "stewing sweet ingredients to moisturize dryness" is an existing practice, and the combination of white radish and rock sugar follows the same idea.

IV. Isothiocyanates and Antibacterial Properties: Where is the Evidence at Now?

White radish belongs to the cruciferous vegetable family and containsGlucosinoside(glucosinolate). When white radish is cut or chewed, its cell structure is disrupted, releasing glucosinolates that react with the plant's own...Black mustard enzyme(myrosinase) contact, hydrolysis to generateIsothiocyanates—That's how the spiciness of white radish comes about.

A Japanese study comparing seven large-root varieties of daikon radish indicated that the most abundant isothiocyanate in daikon radish is MTBITC (4-methylthio-3-butenyl isothiocyanate), which is described in literature as possessing antibacterial and antimutagenic properties (Nakamura et al., 2008, *Journal of Agricultural and Food Chemistry*). This demonstrates that the statement "daikon radish contains antibacterial components" is not unfounded.

But we should view it objectively:These properties were observed under laboratory conditions.The compounds used are isolated or concentrated extracts. Whether drinking a cup of diluted syrup daily can achieve a sufficient concentration in the throat or stomach is currently unestablished. The original text states that "isothiocyanates can activate white blood cells and inhibit bacterial growth," which attributes laboratory-level ingredient activity to human effects—a far-fetched claim. A more appropriate statement would be: white radish is a member of the cruciferous vegetable family, providing dietary fiber, vitamin C, and these plant compounds, making it suitable as part of a balanced diet.

5. Honey for cough relief: Current guidelines already provide the location.

Compared to white radish, honey has a much clearer location for treating coughs, and this clarity is at the "official guidance level."

UK NICE Acute Cough Guidelines (NG120)In the section on self-care, honey is listed as...Children over one year oldOne of the options that people can try is geranium, expectorants containing guaiacol glycerin, and codeine-free cough suppressants; the guidelines also point out that acute coughs usually resolve on their own, and routine use of antibiotics is not recommended. The guidelines mention honey when discussing the mechanism.Demulcent effectAnd the regulation of the cough reflex by sweetness.

A systematic review and meta-analysis of BMJ Evidence-Based Medicine(Abuelgasim et al., including 14 studies) compared honey with routine care, and the results showed:

These figures deserve to be read aloud:Honey showed better results than "general care" in improving symptoms, cough frequency, and severity.This is its positive basis, and also the reason why it is willing to include it in the self-care list; andEvidence for a direct comparison with placebo has not yet been established.This suggests that "sweetness and texture" themselves may play a role. The overall quality of the study was rated as moderate.

The Mayo Clinic's self-care advice for coughs is more direct: "A teaspoon of honey may help relieve a cough," while also reminding patients...Do not give honey to children under one year old.This is because honey may contain bacteria that are harmful to babies.

The sugar composition of honey itself, the complete basis for prohibiting its consumption by infants under one year old, and local quality warnings in Hong Kong (such as mad honey disease) are detailed in another article on this website:<The effects, contraindications, and sugar content of honey>For daily consumption dosage and precautions, please refer to [link/reference].What are the benefits of honey water?For other evidence-based methods to relieve cough, please refer to [link/reference needed].Can chocolate stop a cough?。

VI. How to make and properly preserve Japanese "Daikon Candy"

In Japan, this practice is called "daikon radish candy." Japanese sources often describe it as a "folk remedy said to originate from the Edo period," but there is no single, verifiable original document. A more accurate description would be:A long-standing Japanese family recipe for food therapy。

Material:White radish, honey (the weight ratio of the two is about 2:1, that is, the honey is about half the weight of the radish).

Practice:

1. Wash the white radish thoroughly. Japanese research suggests keeping the outer skin to retain enzymes, so wash it clean and only scrape off a thin layer of the surface.
2. Cut into small cubes about 1 cm in size.
3. Place the radishes in a clean, sterilized, and completely dry glass jar, then pour in honey, ensuring the honey completely covers the radishes.
4. Cover and refrigerate.It takes about 2 hours to 1 day for the radish to release its own water and mix with honey to form a syrup.
5. When drinking, take an appropriate amount and dilute it with warm water (hot water or black tea can also be used as a base). Sip slowly and let the syrup stay in your throat.

save:Refrigerate throughout. Japanese recipes commonly state that it can be stored refrigerated for about two weeks, while others suggest consuming it within 2 to 3 days.Choosing the latter is safer.This is because it is a homemade product that has not been heat-sterilized. If it has an unusual odor, bubbles, abnormal separation, or discoloration, it should be discarded immediately.

VII. The Truth About Sugar: What's the Main Thing You're Drinking in This Cup?

When you combine white radish and honey, it's easy to focus only on the fact that "white radish is healthy." However, the main component of this syrup is actually honey—which is essentially sugar. Here's a comparison per 100 grams:

Honey's sugar content is primarily fructose (approximately 40.9 grams) and glucose (approximately 35.8 grams), with smaller amounts of maltose, sucrose, and galactose. Compared to rock sugar, honey contains about 17% water, resulting in slightly lower sugar and calories per gram—but it is still sugar.

Converted to daily serving size: One teaspoon of honey is approximately 7 grams, containing about 5.8 grams of sugar. The World Health Organization recommends that free sugar intake should be below 101 TP4T of daily energy, with additional benefits for levels below 51 TP4T. Based on a daily intake of 2,000 kcal, 51 TP4T is approximately 25 grams, and one teaspoon of honey accounts for more than 20% of that. The original recommendation was to "drink it 4 to 5 times a day." If sufficient honey is added each time, the accumulated free sugar intake is considerable—drinking it during a cough is fine, but portion control is important, and the rest of the diet should be correspondingly lighter.

The tips from the UK's NHS can be used as a reference for families:Children aged 4 and under should avoid adding sugar.This includes the natural sugars in honey. This is why it's more appropriate for young children to be assessed by healthcare professionals first when they have a cough.

8. Food Safety Considerations for Homemade Syrups

Homemade, raw, and preservative-free – these three conditions combined mean that hygiene and temperature control are particularly important. The Hong Kong Centre for Food Safety's "Basic Information on Food Safety" states that food stored within a dangerous temperature range (4 to 60 degrees Celsius) is prone to bacterial growth; the "2-hour/4-hour rule" applies to food that has been taken from the refrigerator or cooked and left at room temperature – food left at room temperature for more than 4 hours must be discarded.

Applying this principle to honey and white radish syrup, in practice, it can be done as follows:

• Keep refrigerated throughout the process; do not leave it at room temperature.Mix the honey and radish and put them in the refrigerator; after taking them out to drink, put them back immediately and do not leave them at room temperature for more than 2 hours.
• Containers and tools should be cleaned, disinfected, and completely dried first.Make small batches at a time using smaller jars to reduce the need for repeated opening and closing.
• Use a clean, dry spoon to take it.Do not put a spoon that has been in your mouth back into the jar to avoid contamination with saliva.
• Dilute with warm water and do not keep warm for extended periods.Prepare and drink immediately; do not keep it in a thermos and drink it slowly throughout the day.
• Shorten the shelf life.It's better to drink it within 2 to 3 days and then remake it than to leave it for two weeks.
• People with weak immune systems should consult a medical professional first.White radish is a raw vegetable that has not been heated. Pregnant women, infants, the elderly, and people with weakened immune systems should consult medical professionals before consuming it.

To avoid the risks of raw food and homemade foodThe boiled version is a viable alternative.Cut the white radish into chunks, boil it in water until soft, and let it cool to a palatable temperature before adding honey and mixing well (to avoid high temperatures ruining the flavor of the honey). This way, you can retain the sweetness and moisture of the white radish while also eliminating the risk of microorganisms from eating raw food.

9. Who should be paid special attention to? Five types of people.

Additionally, if a cough is accompanied by other symptoms, such as fever, copious yellow-green phlegm, shortness of breath, or wheezing, the priority should be to seek medical attention first to determine the cause, rather than rushing to drink home remedies. Further reading on dietary choices during illness is available.Can I drink milk and eat eggs when I have a cold and fever?。

10. When should you not treat a cough yourself?

Symptom relief requires knowing when it's not applicable. The Mayo Clinic suggests the following:

Seek medical attention as soon as possible:

• The cough has persisted for several weeks without improvement;
• Coughing up thick, yellowish-green phlegm;
• Symptoms include wheezing (whistling sounds during breathing), shortness of breath, and fever;
• Fainting, swelling of the ankles, or unexplained weight loss.

Seek immediate assistance (urgent):

• Choking or vomiting;
• Difficulty breathing or swallowing;
• Coughing up blood or pink sputum;
• Chest pain.

The Hong Kong Centre for Health Protection's recommendations also point out thatAnyone with a cough that lasts for more than a month should seek medical attention promptly.Because a persistent cough may be a sign of an illness that requires treatment. The UK NICE guidelines also advise that if an acute cough does not subside after 3 to 4 weeks, it should be reassessed.

Finally, it's important to clearly draw a line:If a cough is related to asthma, chronic obstructive pulmonary disease, or other respiratory conditions, it falls under the category of requiring medical evaluation and management, and should not be replaced by or delayed with any dietary therapy.For daily care methods for upper respiratory tract infections, please refer to [link/reference].A Balanced Diet: Understanding the Six Food GroupsLet's consider vegetables like white radishes within the overall dietary structure.

XI. Frequently Asked Questions (FAQ)

Can white radish and honey really stop coughing?

It needs to be considered separately. Regarding honey, there is current guidance and a meta-analysis to support its use: the UK NICE guidelines for acute cough list honey as a self-care option that individuals over one year old can try; a meta-analysis of 14 studies published in *BMJ Evidence-Based Medicine* showed that honey was superior to general care in improving overall symptom scores, cough frequency, and cough severity, but evidence comparing it directly to a placebo is still lacking. Regarding white radish, the antibacterial properties of its isothiocyanates are based on laboratory-level observations, and whether they reach sufficient concentrations in humans has not been established; the main benefits of white radish are its water content (over 90%) and vitamin C (22 mg per 100 grams). Therefore, a reasonable assessment is:A mild, palatable symptom-relieving drinkInstead of addressing the underlying cause of the cough.

How many times a day can I drink it? How much each time?

There is no authoritative body to define a standard serving size for this homemade syrup. A reasonable approach is to treat it as a beverage: 2 to 3 times daily, about one tablespoon of syrup diluted in a cup of warm water, sipped slowly to allow the syrup to linger in the throat. The original suggestion of "4 to 5 times daily" is too high in sugar—one teaspoon of honey contains approximately 5.8 grams of sugar; both the frequency and quantity should be moderate, and the rest of the diet should be correspondingly light.

Do I need to peel the white radish?

suggestionDo not peel completely.Japanese research has found that in the common Japanese variety "Aoto Daikon," the myrosinase responsible for converting glucosinolates into isothiocyanates is almost entirely concentrated in the outer peel, while glucosinolates are distributed throughout the entire root tissue. Peeling off the peel is equivalent to removing the enzymes needed for the conversion. Simply wash it clean and scrape off only a thin layer of the surface.

Why can't it be left at room temperature overnight?

Because 4 to 60 degrees Celsius is considered a "dangerous temperature range" by the Centre for Food Safety, bacteria multiply rapidly within this temperature range. The Centre recommends following the "2-hour/4-hour rule," meaning food left at room temperature for more than 4 hours should be discarded. A jar of sugar water left at room temperature overnight far exceeds this time limit. The correct procedure is...Cover and refrigerate.It takes 2 hours to 1 day to extract the syrup – this is also the consistent method in local Japanese recipes.

Can babies under one year old drink this?

Absolutely not.The Hong Kong Centre for Food Safety explicitly advises against feeding honey to infants under one year old because honey may contain Clostridium botulinum spores. Infants' intestinal defense mechanisms are not yet fully developed, and these spores can germinate, multiply, and produce toxins in the intestines, leading to infant botulism. Symptoms include constipation, reduced facial expressions, weak sucking, weak crying, decreased activity, and muscle weakness; severe cases can be fatal. The Centre for Food Safety also reminds parents not to add honey to infant food or apply it to pacifiers. The World Health Organization holds the same opinion.

Can diabetics drink this?

Caution is advised. 100 grams of honey contains approximately 82 grams of sugar, while rock sugar (sucrose) contains approximately 99.8 grams, both of which can affect blood sugar levels. If you are controlling your blood sugar, consult your doctor or registered dietitian before consuming honey, include it in your daily carbohydrate intake, and reduce other sugar sources accordingly. Do not assume that "honey is natural" and therefore can be consumed freely.

Can I use rock sugar instead of honey?

Yes, but you need to know what you're exchanging for. Rock sugar's main component is sucrose, containing nearly 100 grams of sugar per 100 grams. Its sugar and calorie content is higher than honey (honey is about 80% sugar and 17% water). Traditional Chinese medicine's "rock sugar stewing" follows a different approach to "moisturizing dryness," and its effect is not entirely the same as honey's moderating properties. If you choose the rock sugar version, it's recommended to reduce the amount and cook it by stewing for a milder flavor.

How long should a cough last before you need to see a doctor?

Clinically, acute cough is defined as lasting less than 3 weeks, and chronic cough in adults is defined as lasting more than 8 weeks. The practical guidelines are: the UK's NICE (National Health and Welfare Commission) states that acute cough usually resolves on its own within 3 to 4 weeks; if it does not improve after this time, a reassessment is necessary. The Hong Kong Centre for Health Protection recommends that anyone with a cough lasting more than a month should seek medical attention promptly. If fever, thick yellow-green sputum, wheezing, shortness of breath, coughing up blood, or chest pain also occur, immediate medical attention is required.

Is it suitable for people with a lot of phlegm to drink?

The common belief that "honey produces phlegm" is unfounded; however, there is currently no evidence that honey increases respiratory secretions. The sticky feeling in the throat after drinking honey is mainly due to the mucoprotein in the mouth causing the syrup to coagulate and increase in volume, a sensation experienced in the oropharynx. When experiencing excessive phlegm, the proper course of action is to drink enough water, maintain a humid environment, and pay attention to the color of the phlegm and whether it is accompanied by fever—if the phlegm is yellow-green and accompanied by fever, medical attention should be sought.

Can this relieve asthma (wheezing)?

Can't.The original statement that "this formula also has a certain relieving effect on asthma" is an overstatement. Asthma is a chronic respiratory disease that requires evaluation and management by a doctor. If a cough is related to asthma, chronic obstructive pulmonary disease, or other conditions, you must follow your doctor's treatment plan and should not replace or delay proper treatment with any dietary therapy. If you experience difficulty breathing, worsening wheezing, or chest pain, seek help immediately.

Data Sources and Health Disclaimer

• National Institute for Health and Care Excellence (NICE). Cough (acute): antimicrobial prescribing (NG120).Guidelines
• Abuelgasim H, Albury C, Lee J. Effectiveness of honey for symptomatic relief in upper respiratory tract infections: a systematic review and meta-analysis. BMJ Evidence-Based Medicine 2021;26(2):57–64.PubMed Summary
• Mayo Clinic. Cough — Causes and definition / When to see a doctor / Self-care measures。Web page
• NHS. Foods to avoid giving babies and young children(Honey and infant botulism).Web page
• Hong Kong Centre for Food Safety. "Botox Poisoning and Honey."Web page
• Hong Kong Centre for Food Safety, Food Safety Focus, Issue 226. "Honey and Infant Botulism".Web page
• Hong Kong Centre for Food Safety. "High-Risk Food Series: Food Safety Guidelines for Infants and Young Children."Single
• Hong Kong Centre for Food Safety. "Basic Information on Food Safety" (Dangerous Temperature Range and 2-Hour/4-Hour Principle).Web page
• Hong Kong Centre for Food Safety. "Case of 'Rabies Poisoning'".Web page
• Office of Chinese Medicine Regulation, Department of Health, Hong Kong. "Traditional Chinese Medicine Dietary Therapy – Grains and Fruits".Web page
• Hong Kong Centre for Health Protection. Tuberculosis (including the advice that "anyone with a cough lasting more than a month should seek medical attention promptly").Web page
• Nakamura Y, Nakamura K, Asai Y, et al. Comparison of the glucosinolate-myrosinase systems among daikon (Raphanus sativus, Japanese white radish) varieties. Journal of Agricultural and Food Chemistry 2008;56(8):2702–2707.PubMed Summary
• US Department of Agriculture, FoodData Central (Nutritional information on white radish, honey, and sugar).database

This article is a compilation of health information and does not constitute diagnosis or medical advice. Consult a doctor if your cough is persistent, recurring, or accompanied by warning symptoms. Infants, young children, pregnant women, the elderly, and those with weakened immune systems, as well as those taking medication or with chronic illnesses, should consult a healthcare professional before consuming this product. This article does not provide individual dietary or medical advice.

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