Mercury poisoning is treated by removing the source of exposure, using medications that bind to mercury so your body can flush it out through urine, and managing any organ damage that has already occurred. The specific approach depends on which form of mercury you were exposed to, how much entered your body, and which organs are affected.
The First Step: Stop the Exposure
Before any medical treatment begins, the source of mercury needs to be identified and eliminated. This sounds obvious, but mercury exposure is often ongoing and subtle. Common sources include large predatory fish (swordfish, shark, king mackerel, and tuna), older dental amalgam fillings, broken thermometers or fluorescent bulbs, gold mining, and electronic waste recycling. Methylmercury, the organic form, comes almost entirely from seafood. Elemental mercury vapor can come from industrial settings or broken household items containing liquid mercury.
If you suspect mercury exposure, reducing or eliminating the source is the single most important thing you can do. For fish-related exposure, switch to smaller, shorter-lived species like salmon or shrimp, which accumulate far less mercury. Trimming skin or fat from fish does not help, because mercury binds to the muscle tissue itself. If you have older amalgam dental fillings and are concerned, talk to your dentist about replacement options using tooth-colored resin.
How Mercury Levels Are Tested
Doctors use blood, urine, or hair tests depending on your exposure history and symptoms. A 24-hour urine collection is one of the most common methods. According to Mayo Clinic Laboratories, urine mercury above 50 micrograms per 24 hours indicates significant exposure and is considered the threshold where toxicity typically becomes apparent. This is also the benchmark the World Health Organization uses. Your doctor will choose the test type based on whether the exposure was recent or chronic and whether the mercury was organic or inorganic.
Chelation Therapy: The Core Treatment
The primary medical treatment for mercury poisoning is chelation therapy. Chelating agents are drugs that latch onto mercury ions in your body, forming a stable complex that your kidneys can then filter out and excrete in urine. Think of it like a chemical escort service: the drug grabs the mercury and walks it to the exit.
Three chelating agents are used most often:
- Succimer (DMSA): An oral medication taken over about 19 days. It’s often preferred because it can be taken by mouth rather than injected, making it more practical for outpatient treatment.
- Dimercaprol (BAL): Given as a deep intramuscular injection, traditionally recommended for acute poisoning from inorganic mercury salts. Treatment typically lasts 7 to 10 days, with injections given multiple times per day early on and tapering to twice daily.
- Penicillamine: Another oral option, taken four times daily. It’s sometimes used as an alternative when other agents aren’t suitable.
Oral agents like succimer are increasingly preferred over injections for many cases because they’re easier to administer and better tolerated. Your doctor will choose the agent based on the type and severity of poisoning.
Interestingly, research from the American Chemical Society has shown that common chelating agents like DMSA and its cousin DMPS don’t form a perfect one-to-one bond with mercury the way they do with some other metals. Instead, they create more complex multi-molecule structures to capture mercury ions. They still work, but this finding suggests that current chelation drugs may not be ideally designed for mercury specifically.
Treatment Differs by Mercury Type
Not all mercury poisoning is treated the same way, because the different forms of mercury behave differently in your body.
Inorganic Mercury (Salts)
Swallowing inorganic mercury salts is a medical emergency. These compounds are caustic, meaning they burn tissue on contact. Vomiting should not be induced because bringing the mercury back up would cause additional damage to the throat and esophagus. Activated charcoal may be given to bind mercury still in the digestive tract. Aggressive IV hydration is often necessary because of the tissue damage, and kidney function needs close monitoring since inorganic mercury is particularly hard on the kidneys.
Methylmercury (Organic)
This is the form found in contaminated fish and the most common cause of chronic mercury poisoning. It targets the nervous system, potentially causing numbness, vision changes, difficulty with coordination, and cognitive problems. If a large amount was recently swallowed, stomach pumping may be used, especially if mercury is visible on abdominal imaging. A special nonabsorbable resin can help remove methylmercury that cycles through the bile and digestive tract, interrupting the loop that keeps it circulating in your body. Some older research suggests that certain medications may help with the motor function problems methylmercury causes, since it can deplete a key chemical messenger involved in muscle control.
Elemental Mercury Vapor
Breathing in mercury vapor, such as from a broken thermometer or industrial accident, primarily damages the lungs. According to NIOSH guidelines, the first priority is getting the person away from the source and into clean air. Oxygen is given if breathing is difficult, and in severe cases, assisted ventilation may be needed. The initial treatment focuses entirely on supporting breathing and heart function. Fluid given intravenously must be carefully managed because the lungs may already be accumulating fluid.
Side Effects of Chelation Therapy
Chelation therapy is not a gentle process. The drugs that pull mercury out of your tissues don’t exclusively target mercury. They can also strip away essential minerals your body needs, which is why mineral levels are monitored throughout treatment.
Common side effects include fever, headache, muscle pain, nausea, vomiting, and blood pressure changes. Pain at the injection site is typical with dimercaprol. More serious but less common reactions include kidney damage, seizures, trouble breathing, respiratory failure, and heart failure. Because of these risks, chelation therapy is administered under medical supervision with regular lab work to track kidney function and mineral levels.
Supportive Care Beyond Chelation
Chelation removes mercury, but it doesn’t automatically reverse the damage mercury has already done. Depending on which organs were affected, you may need additional treatment. Kidney damage from inorganic mercury can require dialysis in severe cases. Neurological symptoms from methylmercury exposure, like tremors, numbness, or cognitive changes, may persist after mercury levels return to normal and can require rehabilitation or symptom management.
Recovery timelines vary widely. Someone with mild chronic exposure from diet who eliminates the source and undergoes chelation may see improvement within weeks to months. Someone with severe acute poisoning or long-term high-level exposure may have lasting neurological effects even after all detectable mercury is removed.
Protecting Children and Pregnant Women
Mercury is particularly dangerous for developing brains. The FDA and EPA issue specific fish consumption guidelines for pregnant women, breastfeeding women, and young children: eat a variety of fish, choose smaller species, and limit intake to avoid the high-mercury predators like swordfish, shark, king mackerel, and tilefish. If you eat fish caught by family or friends, check local fish advisories. If no advisory exists for that waterway, eat only one serving that week and no other fish.
Mercury accumulates in breast milk, so breastfeeding mothers with known mercury exposure should discuss testing and dietary changes with their healthcare provider. For children, the same chelation agents can be used, but dosing is weight-based and requires careful pediatric oversight because children are more vulnerable to both mercury’s effects and the side effects of treatment.