Baking Soda and Cancer: A Proven Weapon Against Tumors
There is something intellectually uncomfortable about sodium bicarbonate and cancer.
Sodium bicarbonate — ordinary baking soda — is one of the cheapest and most familiar substances in the home. It is not a new pharmaceutical molecule discovered in an expensive laboratory.
bakingIt cannot easily be turned into a proprietary blockbuster drug. Yet a growing body of research suggests that the chemistry of this humble compound may intersect with one of the most important features of cancer biology: the acidity of the tumour microenvironment.
That does not mean that baking soda cures cancer. It does not.
But it does raise a much more interesting question: why has manipulating tumour acidity remained such a relatively marginal idea when conventional oncology has invested enormous resources in targeting the molecular machinery of cancer?
The answer may be less sinister than some critics of modern medicine suggest. But the question itself is entirely legitimate.
An old remedy with an intriguing history
The medical use of bicarbonate long predates modern oncology. A 1925 publication, A Friend in Need, (image above) reproduced advice attributed to a physician who claimed to have used bicarbonate during the 1918–19 influenza pandemic.
The publication described bicarbonate as a means of “alkalinizing” patients and gave a remarkably specific regimen involving Arm & Hammer bicarbonate: six half-teaspoon doses on the first day, four on the second, two on the third, followed by a smaller daily dose.
It is important not to confuse this with evidence that bicarbonate prevented influenza. The document is historical evidence of what was being recommended, not evidence that the treatment actually worked. The distinction matters.
Nevertheless, the historical episode illustrates something that modern medicine sometimes forgets: simple physiological interventions were once considered legitimate subjects for therapeutic experimentation.
Today, we have a much more sophisticated understanding of acid-base physiology — and that understanding has produced an unexpected reason to revisit the chemistry.
Cancer is not chemically neutral
For decades, cancer research concentrated heavily on mutations, oncogenes, tumour-suppressor genes and signalling pathways.
Those things remain fundamental.
But a tumour is not simply a collection of genetically abnormal cells. It exists inside a complicated biological ecosystem consisting of blood vessels, immune cells, connective tissue, metabolites, oxygen gradients and extracellular chemistry.
One particularly important characteristic is acidity.
Many solid tumours have an acidic extracellular environment. Rapid metabolism, lactate production, altered blood flow and poor perfusion all contribute to increased extracellular acidity. Reviews of the subject describe extracellular tumour pH values substantially below normal physiological pH in many solid tumours.
And this acidity is not necessarily an innocent by-product.
It can become part of the tumour’s survival strategy.
Research has associated an acidic tumour environment with increased invasiveness, resistance to apoptosis, suppression of immune-cell activity and resistance to some chemotherapy and radiotherapy. The acidic environment may even contribute to the survival of slow-growing or dormant malignant cells that subsequently become responsible for recurrence.
That changes the question.
Instead of asking only:
How do we kill the cancer cell?
researchers can also ask:
Can we change the environment that enables the cancer cell to survive?
That is where bicarbonate becomes interesting.
The metastasis experiment
One of the most striking experiments was published in Cancer Research in 2009.
Researchers administered sodium bicarbonate to mice carrying breast tumours. The bicarbonate increased the extracellular pH of the tumours without producing the same increase in intracellular tumour pH.
More importantly, the treatment reduced spontaneous metastases in the animal models. It also reduced lymph-node involvement and hepatic metastases in particular experimental settings.
The implication was not that bicarbonate was magically killing cancer cells.
Rather, changing the chemical environment surrounding the tumour appeared to make the cancer less capable of invading and establishing itself elsewhere.
That is a fundamentally different therapeutic concept.
Why acidity may help cancer survive
The mechanism is becoming increasingly interesting.
Acidic conditions can inhibit the activity of cytotoxic T cells and natural killer cells — precisely the cells the immune system needs to attack malignant tissue. They can also promote cellular adaptations associated with survival and treatment resistance.
Acidity may therefore create something resembling a protective ecological niche.
A 2017 review proposed that the acidic tumour microenvironment could constitute a niche supporting dormant tumour cells. These cells can proliferate slowly, evade treatment and survive for prolonged periods before subsequently contributing to relapse.
Interestingly, the same review discusses evidence that returning acid-adapted tumour cells to a more normal pH environment can alter their behaviour, including characteristics associated with proliferation and invasiveness.
Tumour acidity appears to influence dormancy, treatment resistance and immune surveillance — making pH manipulation a rational area for investigation.
And then there is immunotherapy
A 2023 study in a triple-negative breast-cancer mouse model found that oral sodium bicarbonate increased extracellular tumour pH and enhanced the antitumour effects of anti-PD-L1 therapy. Researchers observed increased T-cell infiltration and activation.
And this research is not merely historical.
image above: impact of baking soda on liver cancer williamscancerinstitute.com
In June 2026, researchers reported in Oncogene that intratumoral bicarbonate enhanced PD-1 blockade in hepatocellular carcinoma models. The researchers specifically identified the acidic tumour microenvironment as an immunosuppressive factor and investigated bicarbonate as a means of counteracting it.
So the scientific question has moved beyond “does baking soda kill cancer?”
The more sophisticated question is:
Can manipulating tumour acidity make established cancer treatments work better?
That is a much more credible proposition.
The liver-cancer experiment
Perhaps the most provocative development concerns hepatocellular carcinoma.
Researchers have investigated bicarbonate-integrated transarterial chemoembolization — effectively incorporating alkalinisation into a local cancer treatment delivered to the tumour’s blood supply.
A recent real-world study reported striking results and described previous work in which the investigators had achieved very high rates of locoregional control in unresectable hepatocellular carcinoma.
The mechanism is also being investigated at the cellular level.
Research suggests that alkalinisation can interfere with mitochondrial function, oxidative phosphorylation and autophagy, potentially pushing malignant cells towards cell death.
This is particularly interesting because it illustrates a crucial distinction:
The potentially useful intervention may not be “take baking soda and cure cancer.”
It may instead be:
alter the tumour’s chemistry so that conventional treatment becomes more effective.
That is a much more scientifically defensible hypothesis.
Why isn’t everyone doing it?
This is where the discussion becomes uncomfortable.
A substance costing pennies cannot be commercialised in the same way as a novel molecular drug protected by intellectual-property rights.
There is an obvious economic asymmetry. If a pharmaceutical company spends hundreds of millions developing a novel molecule, successful development can potentially generate decades of commercial returns.
Sodium bicarbonate is different. It is an old, generic chemical. Big Pharma cannot exploit it for profit and chasing profit, not chasing cures, is the business of Big Pharma.
That is not necessarily conspiracy theory. It is economics.
The crucial distinction: promising is not proven
To be clear, there is currently no good evidence that drinking baking soda by itself cures cancer in humans.
The strongest evidence concerns mechanisms, laboratory experiments, animal models and experimental combinations with established treatments. There has been human investigation of oral bicarbonate for cancer-related symptoms and tolerability, but that was a small, non-randomised pilot rather than a definitive efficacy trial.
So, anyone claiming that baking soda is a proven cancer cure is going substantially beyond the evidence.
But the opposite claim — that the idea is simply “quackery” — is also difficult to reconcile with the literature.
There are published experiments demonstrating:
- increased tumour extracellular pH;
- reduced metastasis in some animal models;
- increased effectiveness of certain chemotherapy agents;
- enhanced immune responses;
- improved responses to checkpoint immunotherapy in experimental models;
- biological effects on tumour metabolism and autophagy;
- and clinical investigation of bicarbonate-containing approaches in liver cancer.
That is not proof of a treatment. But it is certainly enough to justify further research. The question is not whether baking soda is a miracle cure. It almost certainly isn’t.
The much more interesting question is whether the chemistry surrounding a tumour has been underappreciated as a therapeutic target — and whether a remarkably cheap molecule has given researchers a clue worth following.
References
- Robey IF, Baggett BK, Kirkpatrick ND, et al. Bicarbonate increases tumor pH and inhibits spontaneous metastases. Cancer Research. 2009;69(6):2260–2268.
Demonstrated in mouse models that oral sodium bicarbonate increased tumour extracellular pH and reduced spontaneous metastasis.
https://aacrjournals.org/cancerres/article/69/6/2260/552860/Bicarbonate-Increases-Tumor-pH-and-Inhibits - Estrella V, Chen T, Lloyd M, et al. Acidity generated by the tumor microenvironment drives local invasion. Cancer Research. 2013;73(5):1524–1535.
Examined how extracellular acidity contributes to tumour invasion and malignant behaviour.
https://pubmed.ncbi.nlm.nih.gov/23329646/ - Corbet C, Feron O. Tumour acidosis: from the passenger to the driver’s seat. Nature Reviews Cancer. 2017;17:577–593.
Review of the biological consequences of tumour acidity, including invasion, immune suppression, treatment resistance and tumour-cell adaptation.
https://pubmed.ncbi.nlm.nih.gov/28331999/ - Gillies RJ, Raghunand N, Garcia-Martin ML, Gatenby RA. pH imaging. A review of pH measurement methods and applications in cancer. IEEE Engineering in Medicine and Biology Magazine. 2004;23(5):57–64.
Discusses methods for measuring tumour acidity and the significance of abnormal pH in cancer.
https://pubmed.ncbi.nlm.nih.gov/15565801/ - Hagendoorn J, et al. Bicarbonate increases tumour pH and inhibits spontaneous metastases. Experimental work underlying the hypothesis that manipulating extracellular tumour pH can alter cancer behaviour.
https://aacrjournals.org/cancerres/article/69/6/2260/552860/Bicarbonate-Increases-Tumor-pH-and-Inhibits - Gerweck LE. Tumor pH: implications for treatment and novel therapeutic strategies. Cancer Research.
Reviews the relationship between extracellular tumour pH and treatment response, including chemotherapy and radiation.
https://pubmed.ncbi.nlm.nih.gov/12649190/ - Daniels G, et al. Sodium bicarbonate enhances the antitumor effect of doxorubicin in experimental models.
Experimental evidence investigating the relationship between extracellular alkalinisation, drug uptake and chemotherapy effectiveness.
https://www.nature.com/articles/6690455.pdf - Sodium bicarbonate enhances the antitumor activity of Doxil in a murine model.
Experimental research examining oral bicarbonate as an adjunct to liposomal doxorubicin and its effect on tumour growth.
https://pubmed.ncbi.nlm.nih.gov/35988781/ - Sodium bicarbonate enhances anti-PD-L1 immunotherapy in a triple-negative breast cancer model.
Experimental evidence that raising tumour extracellular pH can increase immune-cell infiltration and improve checkpoint-immunotherapy responses.
https://pubmed.ncbi.nlm.nih.gov/37894298/ - Bicarbonate enhances PD-1 blockade in hepatocellular carcinoma by modulating the tumour microenvironment. Oncogene. 2026.
Recent experimental work examining intratumoral bicarbonate and its potential to improve immunotherapy in liver-cancer models.
https://www.nature.com/articles/s41388-026-03836-3 - Bicarbonate therapy and hepatocellular carcinoma / transarterial chemoembolization.
Clinical and real-world investigations into incorporating bicarbonate into local treatment approaches for unresectable liver cancer.
https://pmc.ncbi.nlm.nih.gov/articles/PMC12399753/ - ClinicalTrials.gov. Sodium Bicarbonate in Patients With Cancer. NCT01350583.
Clinical investigation of oral sodium bicarbonate, including safety and tolerability considerations.
https://clinicaltrials.gov/study/NCT01350583 - A Friend in Need: A Household Medical Guide. 1925.
Historical household medical guide containing recommendations for sodium bicarbonate during influenza and other illnesses, including a specific dosing schedule. This is evidence of historical medical practice rather than evidence of clinical efficacy.
https://en.wikisource.org/wiki/A_Friend_in_Need_(1925) - National Library of Medicine / MedlinePlus. Sodium Bicarbonate.
Information on recognised uses, precautions, interactions and potential adverse effects of sodium bicarbonate.
https://medlineplus.gov/druginfo/meds/a682001.html
About the author: John O’Sullivan is CEO and co-founder (with Dr Tim Ball among 45 scientists) of Principia Scientific International (PSI). He is a seasoned science writer, retired teacher and legal analyst who assisted skeptic climatologist Dr Ball in defeating UN climate expert, Michael ‘hockey stick’ Mann in the multi-million-dollar ‘science trial of the century‘. From 2010 O’Sullivan led the original ‘Slayers’ group of scientists who compiled the book ‘Slaying the Sky Dragon: Death of the Greenhouse Gas Theory’ debunking alarmist lies about carbon dioxide plus their follow-up climate book. His most recent publication, ‘Slaying the Virus and Vaccine Dragon’ broadens PSI’s critiques of mainstream medical group think and junk science.