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. Sam

    I’ve been a kidney sufferer for a long time and come across this method a thousand times. I have also searched for a scientific explanation of this supposed phenomena before trying it myself. Thank you for conducting the research and putting the results in graspable terms. For whatever reason the above commenters seem to be under the impression that you are trying to hamper progress, when in reality you are removing faulty reasoning. Correlation is not equivalent to causation and the ignorant responses I have read are disheartening. If we don’t understand why a method works, or in this case, doesn’t work, we can never improve in any field. Thank you!

  2. Hallie Glaze

    This works! I don’t show you doing a study yourself on this only presenting facts about the different chemical makeup on the ingredients and how it doesn’t support working. My husband has been suffering for 3 weeks with a kidney stone and we tried this and the next day he was better.

    • Fredric Coe, MD

      Hi Hallie, I am glad it worked for your husband. Unfortunately I have about as many people say it did not as say it did. As for a trial, I have written recently – responses to others – about why that will be hard to organize. Our research group is not trial oriented, but one that is will encounter many barriers. Personally, lacking all data, and given what the ‘treatment’ consists of, I have little reason to believe it will do better than chance. But in your case – husband – things went well, and lets just be happy for it. Regards, Fred Coe

  3. Brock Wright

    Hey guys. I’m a 28 y/o male. Was told I had a 7mm kidney stone almost through to the bladder. I have no health insurance. I’ve been drinking for 3 days a special broth/drink mixture made of kidney bean broth, puree celery, apple cider vinegar, lemon juice, and basil broth. Yesterday I bought a stone breaker tincture made of primarily Chanca Pierda. So I’ve had that going through me for a day and a half. Tonight!… I’ve decided to try and wrap things up with this coke and asparagus remedy. I took a flomax, and just finished the coke and pureed asparagus. I just urinated out something that resembles brown sludge. Approx 7mm long. More details to come… I’m having more bowl movements rather than urine currently.

    • Fredric Coe, MD

      Hi Brock, Be careful. Diarrhea can cause a lot of dehydration so your blood pressure could fall with flomax. Likewise, crystals can form from dehydration, as well. Be sure your physicians know what you are doing, and remain responsible for you. Being young and resilient makes many things safer, but frankly I am concerned. Regards, Fred Coe

      • Brock Wright

        Thanks for the advice and concerns! I immediately began rehydrating after the coke trial. Unfortunately, it did not work. Acted more like a colon cleanse! But three days later after continuing to drink my brothy concoction with the Chance Pierda and constant lemon water… I passed three stones this morning. I’m going to follow up with a uroligost. But I feel like I may be home free until the next stone(s) decide to break loose or form. But again, the coke and asparagus was not helpful for me. Thanks for the great article and advise!

  4. Zac

    Hi.. thanks for the interesting read.. I dont have kidney stones but my elderly friend recommended the coke method if I ever had them.. He used a sieve to collect the stones after he passed them and compared them with the stones without using the method. He said that after using the coke method, the sharp jaggedness had been smoothed out. So the smooth stones are much easier and less painful to pass. There is a lot of anecdotal evidence about this method. Maybe you should conduct a study to get conclusive evidence. You could analyse a batch of kidney stones using and not using the method. Sometimes we only discover mechanisms after observing the results. So just because there isn’t a scientific theory at the moment doesn’t mean that it is impossible. I am a scientist myself, and I have applied the same critical faculty that I use to judge works of science to this article. It seems like your title ‘THE COKE TREATMENT IS USELESS’ is a conclusion you’ve drawn based on a hypothetical argument. You haven’t provided any reference to studies that have looked into the method directly. I think the title should be more like ‘Anecdotal evidence suggests that the coke treatment may make passing stones easier, however the down-sides of coke consumption probably outweigh the benefits’ (I must admit that’s not as catchy as yours though!). I would encourage you to do a proper study into the matter, looking directly at the coke method and how its affects the morphology of the kidney stones. You may uncover a hidden mechanism and come up with a treatment that doesn’t have all the downsides of drinking coke.

    • Fredric Coe, MD

      Hi Zac, You are not wrong. My colleague wanted a catchy title to counter the hype from commercial sources – yes, actually, people sell packs of coke + vegetables as a treatment. As for references, this search on PubMed: ‘coke treatment kidney stones’ – in other words no limiters – gave 0 entries, so I do not think anyone has ever done a trial. As for actually doing a trial – you are a practicing scientist, so I am happy to respond – what is the background out of which to make an hypothesis and an experiment? Coca Cola is a high phosphate low pH beverage whose detailed composition is unknown – trade secret. Because of anecdotes – your word – people believe drinking it at high rates in large volumes along with eating considerable asparagus – multiple species of this veggie and not stated in the anecdotes – will speed up(?) or reduce pain from passage of stones. If that were true, then in a trial of the treatment time needed to pass a stone of a given size (need measures here: time from when to when, how do we do size) will be less than (need a control here) perhaps an equal volume of water (or some better control matched in phosphate and pH but not Coke) consumed at the same rate. Given Coke is a commercial beverage, will NIH pay for this? The trial will cost a fortune – patient selection matching for eex and stone size etc – certainly multicenter and perhaps 5 years to get enough cases. Then there is the problem of real confounders; we use NSAIDS and alpha blockers for stone passage, so we need to match this out, too. Let us say, no difference at 5 years. Will that stop the Coke treatment? I think no, because our control is other fluids, less tasty. Do either the high fluids or Coke help compared to a real control – nothing but usual treatment? That would be a better trial, but now we have three groups – more money, time etc. We would be building a massive scientific undertaking on almost no foundation. Would Coke pay? If they would, there is money. But should they? Would they? What if Coke worsened things in a real trial? You know science: long and hard in human experiments. I have a lifetime of exactly that kind of work. Is the issue worth it to human subjects, given the flimsy underpinnings – anecdote and a lot of hype from companies selling this treatment?

      Your idea is different: morphology change of stones. This would require the same design but omit the need for stone passage time endpoints. But the underpinnings are not so flimsy – visual reports of changes to smoothness. Here, I can imagine a real possibility: People send in their stones from Coke treatment or not, and proper experts (lots of those) determine surface and interior composition etc without knowledge of origin. Lots cheaper. But what if the answer is no? No differences. Will that stop the Coke treatment? Why should it?

      If you have better designs, perhaps someone might want to try them. I am always interested, and the topic has some natural allure. Like folk medicine that sometimes really works – aspirin as an example. Regards, Fred

  5. Dan Farrington

    I’m a long time reader of this site, and enjoyed this article – thanks. I would encourage you all to publish more of these types of articles, as they could help stone formers put facts with what they probably hear or read from time to time. I can’t tell you how many “remedies” seem to exist for kidney stones, based on the consistent recommendations I get from friends, family, and colleagues. In each case, someone they know miraculously had no stones after they followed a careful routine of ingesting something odd that is “known to dissolve stones”. I’m an engineer by profession, and skeptic by personality, so I do my best to listen and thank each and every one of them for their suggestions.

    No, I do not believe that apple cider vinegar dissolved your Grandfather’s stone, I believe that he passed it and drank a large amount of foul liquid for no scientific reason.

    My nephrologist joked about making a coffee table book about all of the bad advice to get rid of stones. Not a bad idea!


    • Fredric Coe, MD

      Hi Dan, Thanks for the refreshing comment. Many remedies are promoted by companies that sell versions of them. All are nonsense. But when you run a site, you get patient and unwilling to quarrel with people who honestly believe in this remedy or that remedy. I will not change their minds and if they are ill I would not add to their aggravations or unhappiness. But in all fairness, sans data, I accept nothing. Best, Fred

  6. william balys

    My dad had 8 kidney stones his late best friend who was a doctor said to drink a 6 pack of coke and a glass o asparagus in a 2 hours period and they will dissolve the next doctor visit they were gone.

    • Fredric Coe, MD

      Hi William, Thanks for sharing. I doubt that stones disappeared unless they were uric acid – even they will not dissolve in Coke. Regards, Fred Coe

  7. Christopher

    I had done this 10 years ago and it worked beautifully. I had pains in my lower back and a minor amount of blood in my urine, the pain was so bad I visited a doctor and surgery was recommended (nope!). I consumed a 6-pack of Coke in an hour, then the broth. Minutes after drinking the asparagus broth I peed like Niagara Falls, 3 times in an hour. I could hear the larger crystals hitting the back of the urinal, and my urine stream was intermittently misdirected or my urine was “slushy” if that makes sense. No more pain, immediately. That’s not a placebo effect. That’s a direct correlation strongly suggesting a causal result to the treatment, and I don’t know how much actual reading of the 108,000-odd Google results you found, but the accompanying countless individual testimonials that are eerily similar to my experience sound an awful lot like evidence to me. Science can often get in the way of common sense.

    • Fredric Coe, MD

      Hi Christopher, Because you have a passionate and philosophical tone, let me try to make my position as clear as possible. First, I have no doubt your own experience is as you say. But what does the word ‘placebo’ mean here? For example, in your case, increased urine from from water alone might have done as much as the coke and vegetable broth. You temporally associate crystal passage with the broth after the coke, but urine flow increase somewhat lags intake so timing can be difficult as a proof the broth added anything. I think by correlation you mean that after the broth stones passed close in time, but I have just pointed out why that may have nothing to do with the mechanisms involved. But let us assume your experiment is as it is said to be: would we not need repetition of the same experiment? This leads to the 108,000 Google entries. They are reports of happy endings, but no more. You might say I am retro and science is in the way of progress and good treatment. But the history of medicine brims over with what we would now call nonsense that once prevailed – blood letting, as an example, with leeches. It ‘worked’; of course it did. Likewise for countless herbs and concoctions. Common sense is not so much wrong as unreliable. Science is not so much in the way as reliable. As a scientist, and physician, I cannot endorse unsupported reports as anything more than that. But I am no censor. I put up all comments that come to this site. It is not so much that I argue with what you write but that outside of science we lack reliability. I represent, for better or worse, what science has given us to the present, and change as it gives us more. Regards, Fred

  8. Aaron

    It worked for a friend of mine. Worked very well in fact. Don’t knock it until you try it for yourself!

    • Fredric Coe, MD

      Hi Arron, Please understand. I am a physician and scientist. Treatments sans supporting data are not usable for me. I cannot recommend them. That your friend believes Coke helped is not a generally helpful kind of information. The placebo effect is powerful. So much so that trial designs are essentially made to allow for it. But I have no emotional attachment to all this. I don’t ‘knock’ it, just require better evidence. Regards, Fred Coe


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