ZismanUCThe featured image points to a widespread idea now on the web concerning how cola drinks might promote kidney stone passage. It has been called the ‘Coke Treatment for Kidney Stones.‘ Fluids are valuable for all stone formers, but the suggested usage may not be ideal and this post points out some of the drawbacks.


A few months ago, a delightful 71-year-old woman presented to our clinic for a metabolic evaluation to try to stop her chronic kidney stones. She passed her first kidney stone about 5 years ago. A year later she developed another kidney stone, which required shockwave lithotripsy therapy. Ultimately her stone was analyzed and she was told it was a “calcium stone.” Over the following few years, she continued to pass one stone per year. More recently, the frequency had increased to a few times per year. Frustrated with the frequent stone recurrences, she sought information online regarding potential remedies for recurrent stone disease. On several websites she came across a remedy known as the “Coke treatment,” which was purported to dissolve kidney stones and prevent stone recurrence. She sent in her payment of $39.97 and received a booklet instructing her to do the following:

  • drink 72 ounces of Coca Cola, ideally not diet or caffeine-free, in 15 minutes or as fast as possible
  • steam and puree one-half pound of asparagus and drink immediately
  • repeat as necessary until kidney stone pain is resolved and stones have passed
  • some variations of this treatment that can be found on the web also recommend drinking water for several hours after the treatment

She dutifully followed the instructions provided and found that on the day of her acute pain, her symptoms did, indeed, abate. Unfortunately, over the next year she found the frequency of her stone attacks actually increased – most recently to as often as passing gravel 2 to 3 times weekly (with significant discomfort). To combat this she has been using the “Coke treatment” about 2-3 times weekly over the last year, creating an apparent vicious cycle (more on that later). Finally, her daughter insisted that she see a physician and so she presented to our office, wondering why her treatment hasn’t been effective.


Using the term ‘Coke treatment of kidney stones’ yielded about 108,000 results, and by page 10 the treatment was still prominent. So cola drinks as a treatment is current.

claim in Internet lore is that phosphoric acid, an additive used in dark colas, when consumed in large quantities can facilitate a reaction within the kidney that will dissolve the calcium oxalate or calcium phosphate admixture that is the kidney stone.  One finds variants of this claim in the discussions by patients.

As I pictured this poor older woman chugging a 6-pack of Coke 2-3 times per week with an asparagus chaser, I was curious to determine whether any potential scientific merit to the internet solution exists.

In short, the answer is No.

Allow me take you through some of the details.


Fluids are Useful

I will start with the 72-ounces of Coca Cola that are to be ingested rapidly. Of course, if one is having acute renal colic with a small stone stuck in a tiny structure like the ureter or urethra, drinking over two liter of fluids of any sort is likely to be beneficial in attempting to propel the stone forward and out of the body. But why Coca Cola? Or any cola for that matter? Is there some reason to believe cola drinks have special properties as a stone treatment?

As far as I can tell, no.

Cola Drinks Are Not a Proven Remedy

Phosphoric Acid as a Stone Dissolver

Phosphoric acid, mixed with nitric acid, is used as a cleaner in the beer industry to remove beerstone (calcium oxalate) from beer kegs. It is also used in home cleaning solutions, as an industrial etchant, and as a rust remover. This leads to the false impression that drinking acid phosphates in beverages will create conditions in the kidneys like those in the beer kegs.

In beer kegs, and when you clean your floor with cleaners, high concentrations of a strong acid are applied directly to the unwanted material.

You Can’t Get Phosphoric Acid into the Urine

But when the small quantities of phosphoric acid found in dark colas are ingested, the first thing that will happen is that calcium and magnesium binding will occur in the gastrointestinal tract. By the time the remaining phosphoric acid is absorbed, additional buffering will occur in the blood and bone, so essentially neutral – not acid – phosphate will be delivered to site of the stone. In studies of a neutral phosphate’s effect on crystal inhibition and dissolution, no evidence of crystal dissolution has been noted.

Effects of Cola in People

How about real people, instead of crystals?

Cola Drinks Raise Stone Risk in Urine

Four subjects were asked to drink three quarts (96 oz) of a dark cola over the course of 48 hours. The researchers then compared the amounts of 3 urine constituents that are known to affect the likelihood of stone formation: magnesium (higher levels in the urine are associated with DECREASED likelihood of stone formation), citrate (higher levels are associated with DECREASED likelihood of stone formation) and oxalate (higher levels are associated with INCREASED likelihood of stone formation). In this study, the average 24-hr magnesium excretion decreased by 2.6 mg, the average citrate excretion decreased by 122 mg, and the average oxalate excretion increased by 8.6 mg.  So in fact, in each of the three constituents, the effect of the cola was a worsening of stone risk.

A larger study performed a few years later confirmed these findings, as well as an associated increase in supersaturation for calcium oxalate in a group of 45 subjects.

Cola Drinks Raise Statistical Risk of Stones

In nearly 200,000 individuals who have been followed over time, Ferraro and colleagues analysed the association between consumption of sugar-sweetened colas and kidney stone formation. Subjects consuming the most sugar sweetened colas were 23% more likely to develop a kidney stone than those in the lowest consumption group. In general cola type drinks are exactly the wrong ones for stone prevention.

Cola Drinks May Pose Other Health Hazards

Sugar and Sodium

The suggested amount of regular Coke in the ‘Coke treatment’ has 840 calories, 270 mg of sodium, and 39 grams of sugar. Taking in that many calories from sugar will almost certainly reduce the amount of other nutrients that one is able to eat or drink in a day, while sugar and sodium are both directly linked to higher urine calcium excretion, a key contributor to nephrolithiasis.

Bone Disease

Whether because of substitution for milk-based drinks, or due to the high acidity associated with soft drinks, consumption of increasing quantities of carbonated beverages has been linked to osteoporosis.

Kidney Disease

In addition to the well known association with diabetes and obesity, a recent report has linked higher consumption of dark colas (2 cans or more per day) with risk of chronic kidney disease.


Ancient Beliefs

Asparagus has been cultivated in the Mediterranean region and in Asia for over 2000 years. Egyptians, Greeks, and Romans believed asparagus to have medicinal properties ranging from treating mood disorders to rheumatism, and a 15th century Arabic sex manual entitled “The Perfumed Garden” claimed asparagus has aphrodisiac properties. It is believed by many to have diuretic properties.

Not Our Asparagus

The usual variety of asparagus that we would buy at the store, Asparagus officinales, is a different species than the medicinal Asparagus racemosa, which is commonly grown in Asia. Furthermore, the medicinal use of asparagus typically involves the root, not the shoot that we typically eat. In Germany, for example, asparagus root is approved by an herbal oversight board as a diuretic whereas the shoot is not recommended.

Not Any Asparagus?

How good is the evidence? Despite what the herbal board says, a recent review found no evidence for human use of the asparagus root as a diuretic. And what if it were a potent diuretic, for argument’s sake? It would have to have specific effects in the distal convoluted segment (a particular region of the kidney tubule), like the thiazide diuretics, to have any beneficial effects on stone prevention –and certainly unlikely to be effective in the acute setting.

So What’s the Harm in a Lot of Asparagus? 

Generally, not much. In normal quantities it is  a healthy vegetable loaded with nutrients such as folate, potassium, and vitamin C. For a stone former, however, there may be hidden dangers with a high asparagus intake. Asparagus has a moderate amount of oxalate, and this amount adds up quickly with repeated administrations of such treatments as the ‘Coke treatment.’ Furthermore, vitamin C is also metabolized to oxalate in the body, adding more of the lithogenic substance to the urine. So, as with most things (except water), it seems that moderation is key.


Looking back,our patient appears to have increased her stone attack frequency with the help of the “Coke treatment” from yearly to several times per week. It seems that the remedy was indeed worse than the disease.

During our visit, in preparation for which she performed several 24-hour urine collections, we determined an individualized plan for her kidney stone treatment based on her urine parameters and a thorough history. With a steady increase in her daily fluid intake and the addition of thiazide therapy, at last check she has had no further stone episodes.


On a hot Summer day, a can of Coke can be delightful. As a medical treatment for kidney stones, no cola is as good as plain water. In the very high doses of the ‘Coke treatment’ there is no benefit predicted from what science we have, and no data to show benefit from a clinical trial. In fact, it would be difficult to organize and perform a clinical trial of the ‘Coke treatment’ because of its evident potential for harm. The trial would be unlikely to pass the human subject protection board review.

Don’t do it.

You Might Want to Read:

Kidney Stone Pain

Fluids to Prevent Stones

Citrate to Prevent Stones

What Stones Are

Types of Kidney Stones






  1. Mark

    Sounds ludicrous to risk getting diabetes from drinking all that cola, I am a sufferer, passed all my stones including 1 that was 1.2cm long and 6.5mm wide, mine are uric mixed with calcium. I just drink plenty of water daily, every morning I have lemon juice shot, mixed in with some apple cider vinegar, cut back on protein, alcohol, sugar and exercised more frequently, haven’t had them for 1.5 yrs. At one stage I had 2-3 per month for 4 months, never had them previous to that and haven’t since. Fingers crossed

  2. Curt

    Dr. Coe. I had to write and Thank-you for your measured responses to the comments here. I am 50 and in the middle of my third (or fourth) kidney stone situation. This one was confirmed by ultrasound and X-ray to be 9mm. I was a pre-med student a long time ago and have a published thesis out there in an Arts vein. I live in a country with health care so I am not motivate by saving money – but it is interesting to see how someone would look for a low cost treatment to a very painful issue. I’ve had two pulmonary embolisms in the past which are the only thing that I’ve ever felt more pain from. I am a Coca-Cola collector, and I drink the stuff. Not every day – but a couple on the weekends. Just reading this has made me consider stopping the “drinking” part. I am almost ashamed to admit that I tried the coke-remedy. I did it because it was easy and something I could do at home. I actually tried it three times. Since the original detction, I have had another x-ray that indicated my 9 mm stone was now 3 mm. I have no idea what specifically shrunk this stone. I’ve been doing a number of things, like drinking a cranberry/lemmon diluted with water solution every day, and taking some other herbal things (under the guidance of a herbologist). I have never been able to catch one of those little painful crystals – so I have no idea what mine comprise of. However, I once again, am thankful for this site and your empirical (Dr. Zissman’s) work on this. I’m heading over to your prevention suggestions right now!

    • Fredric Coe, MD

      Hi Curt, Please let me know what you decide to do after reading about prevention. Regards, Fred Coe

      • Curt

        Dr. Coe. Thank-you for the reply. It looks like the best bet is to stop the process of super-saturation by increasing fluid intake. The 3.5 L is doable (I’m already up to that level). This makes perfect sense. I do have a few questions I hope you might be able to answer:
        (1) Assuming that a person has the occasional super-saturation moment and crystals begin to form. Do the crystals continue to grow even if not in a super-saturated environment (can they be flushed out even if they have been started – if fluid levels are above the 3.5 L mark and all other conditions are normal)? (2) The statistics for Wine, Beer and Coffee drinkers is fascinating. I do not drink any of these items. Are the properties of wine, beer, and coffee such that they inhibit crystal growth, or is it some other factor with people who drink these things (alternatively: should I add these items [in moderation of course] to my diet as another facet to helping prevent stones from forming)?

        Thank-you so much.

      • Curt

        Thank-you for the reply Dr. Coe. I intend to increase my fluid intake to approximately 3.5 L/day or higher if possible. Stopping the number of supersaturations just seems to make sense. I’ll also attempt to limit sodium intake to some degree – or at least increase the fluid intake if I happen to have a little extra sodium. I’ll also lower the cola intake to one or two on the weekend. I do have a couple of questions if I might: (1) If an individual enters a supersaturation state and crystals start to form, but they have made changes so that a majority of the time they are not in that state. Will the crystals continue to grow or can they be flushed out? (2) The statistics on beer, wine and coffee drinkers is fascinating! I have nearly none of this in my diet currently. Is there something in these items that assists a person to be a non-stone-former or is there another factor with people who drink these items (alternatively: I’m looking to add these items [in moderation of course] to my diet to help) – should I add them? (3) Coffee, I assume, should be drunk black?
        Thank-you so much!

        • Fredric Coe, MD

          Hi Curt, Great questions. Lower supersaturations can prevent crystals; apart from uric acid and cystine, they will not dissolve. The good beverages are probably just good fluids without anything bad in them. Coffee is fine. If black means you avoid calcium stop avoiding. High diet calcium will lower urine oxalate and also protect your skeleton. I assume you are a calcium oxalate stone former without a systemic disease causing your stones. If so, read this. The ideal stone diet is the ideal US diet, so any physician can recommend it out of hand. Regards, Fred Coe

      • Princess

        My husband have been also useed cola rc saying by some one for 2 months but not having v good result but have verrrrry small result 1mm or 2
        Please suggest me what should I do?????

        • Fredric Coe, MD

          Hi Princess, The treatment has no basis in fact. What he needs is a proper urological surgeon to protect his kidney and prevent possible loss from obstruction. I would stop fooling around with this and get that surgeon in charge of things. Even a small stone can cause obstruction and a lost kidney. Regards, Fred Coe

  3. Dr. David Vitko

    Prevention beats cures every time!
    Thanks for a great insightful article! You are right. Anecdotal evidence like passing a stone soon after performing a folk remedy like the coke remedy is a poor choice in dealing with any health issue. Since kidney stones often pass on their own within days or weeks, how do you know it would not have happened without the remedy? Scientifically speaking, you cannot say for sure. Odds are the body will normally take care of itself.
    I am a chronic stone former 16 stones in the past 35 years. They would occur every 2 years, alternating kidneys every 2 years. Most passed, although 3 were surgically removed. I was told 2 of them were too big to pass. I have since passed a bigger one on my own. The body is incredibly resilient. It has been 3 years now since my last stone. I chose to finally make a major effort at prevention. I cut out all sugar and have adopted a primarily vegetarian diet with small excursions when I dine out (usually fish). What you do once in a while does no harm. It is what you do every day diet-wise that makes a difference. I lost 30 pounds, which in itself is very helpful with kidney stones. Lastly, I drink 1/2 gallon of water every day. A less concentrated diet helps the kidneys function better as well. By the way my early prostate issues resolved and I stopped snoring at night, sleeping much better. There are so many health benefits to this approach. I love the way I now eat. Hope this helps some fellow stone sufferers!

    • Fredric Coe, MD

      Hi Dr, , Very thoughtful comments what I agree with. Thanks for contributing very sound advice about fluids, the vagaries of stone passage, resiliency, and what it takes to get prevention. Warm Regards, Fred

  4. Jeffrey Jordan

    I have used the asgaragus and coke to cure my last 5 bouts of kidney stones and the longest it took was 3 days. Several times only 24 hours. Start on empty stomach. Drink a 2 liter bottle of regular coke within 2 hours then eat 12 to 16 ounces of steamed asparagus right after finishing the coke. Don’t eat anything else that day. Only drink water. Worked every time for me.

    • Jeff Sidlosky

      It worked for me as well. I had kidney stones twice, the treatment worked within a few hours, the stones were gone along with the days of pain as well.

  5. Steven N Keller

    Has worked amazingly well for me twice and once for my wife.
    I knew within an hour that it was helping.
    If it didn’t work I wasted about $3 and an hour of my time.
    So because it doesn’t work for one person its conclusive evidence that it doesn’t work at all? Thats silly. Most drugs dont work for most people. All drugs work for some people.

  6. David Kailin

    Is there credible evidence for supplemental potassium citrate (or anything else) acting to dissolve stones of various composition? Ditto with respect to dissolution of kidney plaque and plugs?

    • Fredric Coe, MD

      Hi David, Uric acid stones can dissolve when urine pH is increased in any manner – potassium citrate is an example of an alkali agent. Plaque is in the kidney tissue and how it is made and perhaps removed biologically an area of present research. Plugs are in tubules and cannot be dissolved. I suspect tubules somehow repair themselves but have no evidence as yet. Great questions, thank you, Fred Coe

      • David Kailin

        What theoretical and applied approaches are being considered and tested for kidney tissue plaque removal?
        Why might one choose to combine alkalizing agents, specifically potassium citrate and potassium bicarbonate?
        Do I gather correctly that there is no substance scientifically verified that safely dissolves calcium stones in vivo?
        Thank you for such an informative – and artful – website!

        • Fredric Coe, MD

          Hi David, Plaque removal has not as yet found its way into any workable science. The mechanisms of plaque formation remain uncertain. I suspect plaque is naturally shed from the tissues and the secret is to slow production, and I have ideas, but no results.

          As for alkali, some people cannot excrete potassium normally and cannot be given potassium loads. Others cannot stand the GI effects of the potassium. SOdium alkali are not ideal because the sodium load raises urine calcium – and in some people blood pressure. But in uric acid stone formers, as an example, they can work fine. As for dissolving calcium stones in the kidneys, we have nothing. Chelating agents are toxic. Regards, Fred Coe

  7. thangaraj

    hi sir

    i am read article usually coco cola and pepsi is not suitable for health,and cola drinks causes kidney stones,is it really

  8. Lee hawthorn

    Hey , everything seems great . I no longer have the kidney stone symptoms . I am going to stay with the recommended daily dose of Apple Cider Vinegar . I have found that it goes down better and tastes better by mixing it with grapefruit juice . Nothing but smiles here .:)

    • Fredric Coe, MD

      Hi Lee, I am glad you have found yourself a remedy. I do have to make clear that I do not endorse the product but I also cannot see anything much wrong with it, either.
      Regards, Fred Coe

  9. Dawn Hadley

    Seriously 5 kidney stones is chronic stone disease?? Please tell me it’s a joke!! I actually have chronic stone disease!!!!! I pass stones every week, sometimes every day, for 17 years!!! I’ve had over 400 stones removed at once at John’s Hopkins in Maryland. Most people that have a kidney stone will get another one, 5 stones in 5 years is not uncommon. This article is extremely insulting to the people who actually have chronic stones I can’t believe somebody would use the word “chronic” without actually knowing what it means. And for anybody actually considering that “remedy” – if you drink 72 ounces of any liquid in 15 mins you’ll pass your stone fast, the Coke has absolutely nothing to do with it. Plus if you make oxalate stones than the Coke will help you to make more kidney stones!!

  10. Bruce Gomes

    1) The studies all cited concerning Cola appeared to always specify Cola with sugar – is there a reason that matters? Is there any reason to believe that Diet Cola wouldn’t carry the same risks of raising the probability of kidney stone formation? (assuming there are risks..) 2) The press appeared to include any dark colored soda in this category, and often cited root beer – one I have uses Malic acid, part of the Citric acid cycle – so is that not applicable to a problem involving Phosphoric acid?


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