Sodium bicarbonate, commonly known as baking soda, is not toxic at the small amounts used in cooking and occasional antacid use. It becomes dangerous when consumed in large quantities or used regularly at high doses. The threshold where problems begin is around 4 grams in a single dose for antacid purposes, and animal studies place the lethal dose extremely high, above 4,000 mg per kilogram of body weight. For a 150-pound adult, that translates to roughly 270 grams or more, an amount no one would consume by accident in food.
How Much Is Too Much
The amount of baking soda in a batch of cookies or a loaf of bread is trivial, typically a teaspoon or less shared across multiple servings. That poses zero risk. The concern starts when people use baking soda as a home remedy, dissolving spoonfuls in water for heartburn, indigestion, or other purposes found online.
Mayo Clinic dosing guidelines cap the daily amount at roughly 4 teaspoons of baking soda powder (around 16 grams) when used to make urine less acidic, and no more than 5 teaspoons a day of effervescent powder for heartburn. Individual doses for heartburn should stay below 4 grams. These limits exist because exceeding them can push your blood chemistry out of balance, even though the substance itself isn’t a classic poison.
What Happens When You Take Too Much
Your blood naturally maintains a narrow pH range. When you flood your system with bicarbonate, it shifts that balance toward the alkaline side, a condition called metabolic alkalosis. Under normal circumstances, your kidneys can handle a moderate excess by simply flushing the extra bicarbonate into your urine. But when the amount overwhelms that capacity, or when kidney function is already compromised, the alkalosis takes hold and symptoms follow.
The early signs of a baking soda overdose include nausea, vomiting, diarrhea, and a bloated or overly full feeling. As things escalate, you may experience muscle spasms, muscle weakness, irritability, frequent urination, and in serious cases, convulsions. The vomiting and diarrhea themselves create a secondary problem: dehydration and electrolyte imbalances that can trigger dangerous heart rhythm disturbances.
Risks of Regular High-Dose Use
A single large dose isn’t the only concern. People who routinely take baking soda for chronic heartburn or as part of folk remedies can develop sustained metabolic alkalosis over time. The body adapts in ways that make the condition self-reinforcing: the kidneys begin reabsorbing more bicarbonate from filtered blood rather than excreting it, which locks the alkalosis in place even at lower ongoing doses.
Chronic overuse also loads your body with sodium. Each teaspoon of baking soda contains about 1,260 mg of sodium, more than half the recommended daily limit. Over weeks or months, this extra sodium raises blood pressure and strains the cardiovascular system. For anyone with existing kidney disease, heart failure, or high blood pressure, even moderate regular use can be harmful. The kidneys, already working to manage the sodium and pH load, can suffer further damage.
Who Is Most Vulnerable
Children are at higher risk because their smaller body weight means a given teaspoon represents a much larger dose per kilogram. A home remedy dose that might cause mild stomach upset in an adult could trigger convulsions or serious electrolyte disruption in a young child. Older adults with reduced kidney function are similarly vulnerable, since their ability to clear excess bicarbonate is diminished.
People taking certain medications, particularly diuretics or drugs that affect kidney function, face compounding risks. The combination can amplify electrolyte imbalances beyond what either the drug or the baking soda would cause alone.
What an Overdose Looks Like
Most baking soda overdoses happen at home, often when someone drinks a large glass of dissolved baking soda for indigestion or follows an internet protocol calling for multiple daily doses. The onset is usually rapid: within an hour, nausea and vomiting begin. If the dose was high enough, muscle twitching, weakness, and confusion follow as electrolytes shift. In the most severe reported cases, heart rhythm disturbances and seizures have occurred.
Treatment in an emergency setting focuses on restoring fluid balance and correcting electrolyte levels. There is no specific antidote. The body can recover on its own once the source is removed and fluids are replaced, but the window between “uncomfortable” and “dangerous” can be narrow, particularly if vomiting prevents the person from staying hydrated.
Safe Use in Practice
Baking soda in food is safe. As an occasional antacid, a half teaspoon dissolved in water is the standard single dose, and most people tolerate it without issue. Problems arise from exceeding 4 grams per dose, taking multiple doses throughout the day, or using it daily over extended periods. If you find yourself reaching for baking soda regularly for stomach issues, that pattern itself signals an underlying problem worth addressing rather than masking with a kitchen remedy.