Chelation therapy is the cornerstone of arsenic poisoning treatment, using drugs that bind arsenic in the body and pull it out through urine. The specific chelating agent, the urgency of supportive care, and the additional interventions all depend on whether the poisoning is acute (a single large exposure) or chronic (low-level exposure over months or years). In acute cases, treatment is a medical emergency requiring hospital-based stabilization alongside chelation; in chronic cases, removing the source of exposure is the single most important step, with chelation and nutritional strategies playing supporting roles.
How Chelation Therapy Works Against Arsenic
Arsenic in its most toxic inorganic forms interacts readily with sulfur-containing proteins in the body, disrupting enzymes and damaging cells across multiple organ systems. Chelation drugs exploit the same chemistry: they contain sulfur-based groups that bind arsenic more tightly than the body’s own proteins do, forming a complex that the kidneys can then filter out. The goal is to pull arsenic out of tissues and into the bloodstream, then out through urine, before the metal causes irreversible damage to the kidneys, liver, heart, and nervous system.
The classic chelator for arsenic is dimercaprol, often called BAL (British Anti-Lewisite), developed during World War II as an antidote for arsenic-based chemical weapons. BAL is still used in severe acute poisonings, but it comes with significant downsides: it must be given by painful intramuscular injection, it has a narrow margin between a helpful dose and a harmful one, it has an intensely unpleasant smell, and it can actually redistribute arsenic into the brain and testes.1PubMed. Are we ready to replace dimercaprol (BAL) as an arsenic antidote? For the most critical cases, where every minute counts, BAL may still be the first drug given simply because it works fast and is widely available in hospital settings. But the toxicology community has largely moved toward newer alternatives whenever possible.
DMSA and DMPS as Preferred Chelation Agents
Two water-soluble chelators, DMSA (succimer) and DMPS (unithiol), have largely replaced BAL for most arsenic poisoning scenarios. Both can be taken by mouth, which is a major practical advantage over BAL’s injections. In animal studies, both proved more effective than BAL at equivalent doses when given soon after poisoning, and both are considerably less toxic. DMSA showed the strongest protective effect in mice given arsenic trioxide, outperforming DMPS and BAL by wide margins when treatment started immediately after exposure.2PubMed. Efficacy of various dithiol compounds in acute As2O3 poisoning in mice When treatment was delayed by thirty minutes, both DMSA and DMPS still outperformed BAL, though the gap narrowed. Research in mice comparing DMSA and DMPS directly for clearing arsenic from liver and kidney tissue found DMSA to be more effective at reducing arsenic levels in those organs.3Austin Publishing Group. Chemoprevention of Arseniasis-Past, Present and Future (Mini Review) – Section: Chelation of Arsenic
In practice, the choice between DMSA and DMPS often depends on what is available. DMSA is FDA-approved in the United States (for lead poisoning, but used off-label for arsenic), while DMPS is more widely used in Europe and parts of Asia. Both are given orally once the patient can swallow and keep medication down. In severe poisoning where the patient is vomiting or unconscious, DMPS can also be given intravenously — a case report of arsenic trioxide ingestion from a suicide attempt described successful early treatment with intravenous DMPS alongside gastric lavage and fluid replacement.4Hong Kong Journal of Emergency Medicine. Attempted suicide by poisoning of self‐prepared arsenic trioxide solution – Section: Discussion
D-Penicillamine as a Second-Line Option
D-penicillamine is an older oral chelator that binds arsenic and increases its excretion in urine. It is not as potent as DMSA or DMPS, but it has a role when those drugs are unavailable or when a patient needs prolonged oral chelation after initial stabilization. A case series of three children who survived acute arsenic poisoning documented that D-penicillamine, given at four daily doses, effectively increased arsenic excretion over multiple days of treatment.5PubMed. D-penicillamine therapy of acute arsenic poisoning In another case, a patient received D-penicillamine alongside activated charcoal for gastrointestinal decontamination, N-acetylcysteine (NAC) as an antioxidant support, and dialysis for kidney failure that developed as a complication.6PubMed Central. Acute Arsenic Poisoning: A Case Report and Literature Review – Section: Abstract D-penicillamine is generally considered a backup, not a first choice, for arsenic chelation.
Emergency Supportive Care in Acute Poisoning
Chelation alone does not save lives in severe acute arsenic poisoning. The immediate threats are cardiovascular collapse, severe dehydration from profuse vomiting and diarrhea, kidney failure, and potentially fatal heart rhythm disturbances. Emergency treatment addresses all of these simultaneously.
The first priorities are protecting the airway (arsenic poisoning causes intense vomiting, and aspiration is a real danger), starting aggressive intravenous fluids to counter dehydration and support blood pressure, and decontaminating the gastrointestinal tract if the patient arrives soon enough after ingestion. Gastric lavage and activated charcoal have both been used in reported cases, though charcoal does not bind arsenic particularly well and is most useful if the patient has ingested other substances alongside the arsenic.
Kidney function needs close monitoring. Arsenic is nephrotoxic, and acute kidney injury can develop rapidly. If urine output drops or kidney markers spike, dialysis may be needed as organ support. The evidence on whether dialysis actually removes meaningful amounts of arsenic from the body is mixed, as discussed below. But as a tool for keeping the kidneys alive long enough for chelation to work, it has clear value.
Does Dialysis Remove Arsenic?
This is a genuinely unsettled question in toxicology. One early case report found that four hours of hemodialysis produced a striking drop in blood arsenic levels in a patient who had acute kidney failure, and the authors concluded dialysis was appropriate when kidney function is impaired.7PubMed. Hemodialysis of acute arsenic intoxication with transient renal failure But another case involving massive ingestion found that neither standard hemodialysis nor hemoperfusion (a more aggressive blood-filtering technique) produced any measurable reduction in arsenic levels, and the patient did not improve.8PubMed. Results of hemodialysis & hemoperfusion in the treatment of acute arsenic ingestion
The likely explanation is that arsenic binds tightly to tissues within hours of absorption, meaning there is a narrow window during which a significant amount is still circulating in the blood and available for removal by dialysis. Once arsenic has distributed into the liver, kidneys, and other organs, dialysis cannot pull it back out. The current clinical consensus is that dialysis is indicated when the patient develops kidney failure (to support the organ), but should not be relied upon as a primary method of arsenic removal. Chelation remains the main tool for getting arsenic out of the body.
Cardiac Monitoring and Heart Rhythm Dangers
One of the more dangerous complications of arsenic poisoning is its effect on the heart’s electrical system. Arsenic blocks potassium channels that control how the heart resets between beats, which can prolong a measurement on the electrocardiogram called the QT interval. When the QT interval stretches too far, the heart becomes vulnerable to a chaotic, potentially fatal rhythm called torsades de pointes.9PubMed. Torsades de pointes in 3 patients with leukemia treated with arsenic trioxide Low potassium and low magnesium levels in the blood make this risk even worse.
What makes arsenic-induced heart rhythm problems especially treacherous is that they tend to resist the usual treatments. Standard electrical cardioversion and most anti-arrhythmic drugs are often ineffective.10PubMed. Torsades de pointes in 3 patients with leukemia treated with arsenic trioxide Aggressive correction of electrolyte levels — keeping potassium and magnesium high-normal — is the main preventive strategy. In clinical settings where arsenic trioxide is used therapeutically (for a type of leukemia), patients routinely get continuous cardiac monitoring and electrolyte supplementation for this reason. Chelation and dialysis have not been shown to help with the cardiac electrical effects once the QT interval is already prolonged.11JACC. BOTH THE POISON AND THE CURE: TORSADES DE POINTES INDUCED BY CHEMOTHERAPEUTIC ARSENIC TRIOXIDE – Section: Decision-making The QT prolongation can persist for weeks after the last arsenic exposure, meaning cardiac surveillance needs to continue well beyond the acute treatment phase.
A Different Problem Entirely — Treating Chronic Arsenicosis
The treatment framework above applies to acute poisoning, where someone ingests or inhales a large dose over a short time. Chronic arsenicosis is a completely different clinical problem. Millions of people worldwide, particularly in Bangladesh, parts of India, and some areas of the Americas, are exposed to low levels of arsenic through contaminated drinking water over years or decades. The resulting disease affects the skin (dark patches, thick calluses on palms and soles), the peripheral nerves, the liver, and eventually raises the risk of cancers of the skin, lung, and bladder.12PubMed. Arsenic carcinogenesis in the skin
For chronic arsenicosis, the single most impactful treatment is removing the source. Water filtration systems designed to remove arsenic from private wells have been shown to reduce arsenic concentrations by up to a hundredfold, with one study in Maine and New Jersey finding that treated wells dropped from a median of about 72 micrograms per liter to less than 1 microgram per liter, cutting estimated skin cancer risk by roughly sevenfold.13PubMed Central. Reduction in drinking water arsenic exposure and health risk through arsenic treatment among private well households in Maine and New Jersey, USA – Section: Results and Discussion Point-of-entry systems that treat all water coming into the house performed better than point-of-use filters at the tap, and professionally maintained systems had lower failure rates than homeowner-installed ones.
The skin manifestations of chronic arsenic exposure are managed with topical and systemic treatments. Salicylic acid at five to ten percent concentration can reduce the thick, scaly skin on palms and soles. When skin changes progress toward precancerous or cancerous lesions, oral retinoids like acitretin have shown benefit in case reports, typically at doses ranging from 10 to 25 milligrams per day. Standard surgical and dermatological treatments for skin cancers remain effective even in patients whose cancers were triggered by chronic arsenic exposure.14PubMed Central. Cutaneous manifestations and treatment of arsenic toxicity: A systematic review – Section: Treatment of chronic arsenic toxicity dermatological presentations
Folic Acid and the Methylation Pathway
The body detoxifies arsenic primarily by methylating it — adding methyl groups to the arsenic molecule, which makes it less toxic and easier for the kidneys to excrete. This process depends on folate (vitamin B9), vitamin B12, and a functioning methylation cycle. People who are folate-deficient methylate arsenic poorly, leaving more of the toxic unmethylated forms circulating in their bodies.
A landmark trial in Bangladesh gave folic acid supplements to adults with low plasma folate who were chronically exposed to arsenic through drinking water. After supplementation, the proportion of arsenic excreted in its least toxic, fully methylated form rose from about 72% to 79%, while the more toxic partially methylated and unmethylated forms dropped significantly.15PubMed Central. Folate and arsenic metabolism: a double-blind, placebo-controlled folic acid-supplementation trial in Bangladesh – Section: RESULTS A subsequent trial confirmed that folic acid supplementation shifted arsenic metabolism toward safer forms by six weeks, with or without the addition of creatine.16The American Journal of Clinical Nutrition. Folic Acid and Creatine as Therapeutic Approaches to Lower Blood Arsenic: A Randomized Controlled Trial – Section: RESULTS The same approach has now been tested in children. A double-blind trial supplementing Bangladeshi children with folic acid and B12 confirmed that the combination increased arsenic methylation in both blood and urine, suggesting nutritional interventions could reduce arsenic toxicity in chronically exposed populations, including kids.17PubMed Central. Influence of folic acid and vitamin B12 supplementation on arsenic methylation: A double-blinded, placebo-controlled trial in Bangladeshi children – Section: CONCLUSION
Folic acid supplementation is not a substitute for removing the arsenic source or for chelation in acute poisoning. But for the millions of people living with chronic low-level exposure who cannot immediately switch to clean water, it is one of the most practical and inexpensive interventions available.
Selenium, Antioxidants, and Investigational Approaches
Arsenic causes a large part of its damage through oxidative stress — generating reactive molecules that tear through cell membranes, DNA, and proteins. This has led researchers to study whether antioxidant nutrients can blunt some of that damage in chronically exposed populations.
Selenium has shown the most consistent protective effects in animal studies. Rats given high-selenium lentil diets alongside chronic arsenic exposure had better antioxidant levels, stronger immune responses, and excreted more arsenic in feces and urine compared to selenium-deficient animals.18PubMed. Treating chronic arsenic toxicity with high selenium lentil diets Zinc and selenium together have also been shown to reverse liver damage from heavy metal mixtures including arsenic in experimental animals.19PubMed. Selenium and zinc alleviate hepatotoxicity induced by heavy metal mixture (cadmium, mercury, lead and arsenic) via attenuation of inflammo-oxidant pathways
Curcumin, the active compound in turmeric, has attracted considerable research interest. Animal studies have found that curcumin reduced arsenic-induced liver damage, restored depleted antioxidant enzymes, and promoted arsenic methylation and urinary excretion.20PubMed. Curcumin attenuates arsenic-induced hepatic injuries and oxidative stress in experimental mice through activation of Nrf2 pathway, promotion of arsenic methylation and urinary excretion Other experiments showed curcumin protected brain tissue from arsenic damage, partially restoring levels of key neurotransmitters that arsenic had depleted.21PubMed. Neuroprotective effect of curcumin in arsenic-induced neurotoxicity in rats Higher doses appeared more protective in a dose-dependent fashion across liver and kidney tissues.22PubMed. Ameliorative mechanisms of turmeric-extracted curcumin on arsenic (As)-induced biochemical alterations, oxidative damage, and impaired organ functions in rats
The honest caveat here is that nearly all of this work is in rodents. Curcumin is notoriously difficult to translate from animal models to human medicine because it is poorly absorbed in the gut and broken down rapidly. Selenium supplementation in humans also carries its own toxicity risk at high doses. Neither selenium nor curcumin should be treated as proven treatments, but they represent the direction much current research is heading for populations with ongoing chronic exposure.
Diagnosis Is Harder Than It Sounds
Getting the right treatment depends on getting the right diagnosis, and arsenic poisoning is easy to miss. Acute symptoms — vomiting, diarrhea, abdominal pain, garlic breath — can mimic gastroenteritis or food poisoning. Chronic exposure produces vague symptoms (fatigue, numbness in hands and feet, skin changes) that overlap with dozens of other conditions. A clinician has to think of arsenic to test for it.
The standard diagnostic test is a 24-hour urine arsenic level. Spot urine tests are also used but give a less complete picture. Blood arsenic levels are useful in acute exposure but drop quickly as arsenic moves into tissues. Hair and nail analysis can reflect longer-term exposure, since arsenic deposits in keratin-rich tissues as it grows out. However, hair analysis has a significant limitation: external contamination from arsenic-containing dust or water can deposit arsenic on the hair surface, making it difficult to distinguish environmental contamination from genuine systemic poisoning. The current view is that hair analysis works as a screening tool, but clinical symptoms and urine testing are needed to confirm a diagnosis.23PubMed Central. On the Use of Hair Analysis for Assessing Arsenic Intoxication – Section: Abstract
Genetic variation matters too. Some people carry gene variants that make their methylation enzymes less efficient, meaning they process and excrete arsenic more slowly than average. These individuals accumulate higher internal doses from the same external exposure, and may develop symptoms at exposure levels that would not bother someone with faster methylation. Identifying these variations could eventually help clinicians target treatment more precisely, but routine genetic testing for arsenic susceptibility is not yet standard practice.
Pediatric Considerations
Children present unique treatment challenges. Their smaller body mass means a given amount of arsenic represents a proportionally larger dose, and their developing organs may be more vulnerable. On the positive side, a case report of a toddler who ingested sodium arsenate showed that chelation with BAL followed by oral D-penicillamine and then DMSA cleared arsenic efficiently, with a urinary excretion half-life of roughly two and a half days — at least two to three times faster than what would be expected for spontaneous excretion in adults.24The American Journal of Emergency Medicine. Brief report Pediatric arsenic ingestion – Section: Abstract The child recovered fully, with normal kidney and liver function throughout treatment.
Folic acid and B12 supplementation for children with chronic exposure is also being actively studied, with the Bangladeshi trial described earlier showing that the supplements improved arsenic methylation and excretion in children just as they did in adults.25PubMed Central. Influence of folic acid and vitamin B12 supplementation on arsenic methylation: A double-blinded, placebo-controlled trial in Bangladeshi children – Section: CONCLUSION
The Gut Microbiome as a Wild Card
An area of research that could reshape how we think about arsenic treatment is the role of gut bacteria. The microbiome does not passively sit by while arsenic passes through the digestive tract. Gut bacteria can chemically transform arsenic compounds, changing their toxicity in the process. Some bacterial species methylate arsenic (generally making it less toxic and easier to excrete), while others convert arsenic into highly toxic intermediary forms.26PubMed Central. The Human Gut Microbiome’s Influence on Arsenic Toxicity – Section: Abstract
In vitro experiments simulating colon digestion found that gut microbes could methylate arsenic at significant rates, and, more worryingly, produced monomethylarsonous acid, one of the most toxic arsenic species known. They also generated a thiolated arsenic metabolite whose toxicity is not yet well characterized.27Environmental Health Perspectives. Arsenic Metabolism by Human Gut Microbiota upon in Vitro Digestion of Contaminated Soils – Section: Results Certain bacterial groups, including Bacteroides and Clostridium species, appear to have arsenic resistance and the ability to methylate it, and dietary factors like iron can alter which bacteria dominate and thereby shift arsenic metabolism.28PubMed. Arsenic Metabolism and Toxicity Influenced by Ferric Iron in Simulated Gastrointestinal Tract and the Roles of Gut Microbiota
None of this has translated into a microbiome-based treatment yet, but it raises important questions. Could probiotics someday shift gut arsenic metabolism toward less toxic forms? Could antibiotic use inadvertently worsen arsenic toxicity by disrupting beneficial bacterial populations? Animal studies in which the gut microbiome was disrupted showed altered arsenic excretion and body burden, suggesting the answer to both questions may be yes.29PubMed Central. The Human Gut Microbiome’s Influence on Arsenic Toxicity – Section: Abstract For now, the practical takeaway is that gut health may matter more to arsenic detoxification than anyone appreciated a decade ago.
Arsenic as Medicine and What That Teaches Us About Toxicity
Arsenic trioxide is paradoxically one of the most effective drugs for treating acute promyelocytic leukemia, a blood cancer. Chinese physicians began using it for this purpose in the 1970s, and accumulated clinical experience has shown that carefully dosed intravenous arsenic trioxide is both remarkably effective and tolerable in patients with this specific leukemia, including those who have relapsed after other treatments.30PubMed. History of the development of arsenic derivatives in cancer therapy The drug works by forcing the cancer cells to mature and then die, a mechanism distinct from conventional chemotherapy.
The fact that arsenic is both a deadly poison and a life-saving drug at different doses illustrates a core principle in toxicology. Patients receiving arsenic trioxide for leukemia undergo the same cardiac monitoring and electrolyte management described earlier for poisoning victims, because the QT prolongation risk is identical. The difference is dosing and control. Understanding how arsenic is managed therapeutically has directly informed how it is managed as a poison, and vice versa — a rare case where the disease and the treatment share not just a mechanism but the same molecule.