Sodium bicarbonate, commonly known as baking soda, is one of the most versatile chemical compounds in everyday life. It serves as a leavening agent in cooking, an over-the-counter antacid for heartburn, a performance supplement for athletes, and a critical treatment in emergency medicine. Its usefulness comes down to one core property: it’s a mild alkaline substance that neutralizes acids and releases carbon dioxide gas in the process.
Heartburn and Indigestion Relief
The most familiar medical use of sodium bicarbonate is as a fast-acting antacid. When you swallow it, the compound reacts with hydrochloric acid in your stomach, neutralizing excess acid and relieving that burning sensation. For adults, the typical dose is half a teaspoon dissolved in a glass of water every two hours, or 325 mg to 2 grams in tablet form one to four times a day. Children aged 6 to 12 use smaller amounts, usually around a quarter to half teaspoon in cold water after meals.
The relief is quick but temporary. Sodium bicarbonate is not meant for long-term use as an antacid. The Mayo Clinic advises against taking it for more than two weeks straight. If heartburn keeps returning, that’s a signal to investigate the underlying cause rather than continuing to neutralize the acid.
Slowing Kidney Disease Progression
Healthy kidneys help regulate your blood’s acid-base balance, but as kidney function declines, acid can build up in the blood, a condition called metabolic acidosis. This excess acid, in turn, accelerates kidney damage, creating a destructive cycle. Oral sodium bicarbonate breaks that cycle by supplementing the bicarbonate your kidneys can no longer produce on their own.
A three-year randomized trial of 740 patients with moderate to advanced chronic kidney disease found that oral sodium bicarbonate corrected metabolic acidosis, slowed the progression of kidney disease, and decreased overall mortality. Another study showed it reduced the number of patients experiencing a 40% or greater decline in kidney filtration rate, a threshold that often leads to kidney failure. Clinical guidelines from the National Kidney Foundation recommend starting at 650 mg twice daily and adjusting based on response, with typical doses ranging from 0.5 to 1.0 milliequivalents per kilogram of body weight per day.
Treating Severe Acidosis in Hospitals
When blood becomes dangerously acidic (a pH below 7.20), the body’s cardiovascular system starts to fail. Severe acidosis weakens the heart’s ability to contract, blunts the effect of blood-pressure-supporting medications, and reduces the liver’s capacity to clear lactic acid. In these situations, intravenous sodium bicarbonate acts as a buffer, directly raising blood pH toward a safer range.
This treatment is most clearly supported in patients who also have acute kidney injury, where the kidneys can’t correct the imbalance on their own. One complication is that the buffering reaction itself produces carbon dioxide, which can worsen the problem if the patient’s lungs can’t clear it quickly enough. It can also lower ionized calcium levels, which further strains the heart. For these reasons, the target is modest: raising blood pH to 7.20 to 7.25, not to normal levels.
Poisoning and Overdose Emergencies
Sodium bicarbonate plays a specific, life-saving role in certain types of poisoning. In tricyclic antidepressant overdoses, the drug blocks sodium channels in the heart, widening the electrical signal (the QRS complex on an EKG) and triggering dangerous heart rhythms. Sodium bicarbonate counteracts this in two ways: the sodium ions help reopen blocked channels, and the rise in blood pH causes the drug to detach from heart tissue and bind to proteins in the blood instead, effectively pulling it away from where it does damage.
In aspirin (salicylate) overdoses, the goal is different. Making the blood and urine more alkaline converts salicylate into a form that can’t cross back out of the kidneys, trapping it in the urine so the body eliminates it faster. This “ion trapping” technique significantly increases how quickly the drug is cleared.
Cardiac Arrest: Limited Evidence
For decades, sodium bicarbonate was given routinely during CPR on the theory that cardiac arrest causes dangerous acid buildup. The American Heart Association’s 2025 guidelines, however, confirm that routine use during cardiac arrest provides no clear benefit. Some recent observational data hint at a possible survival advantage in specific types of cardiac arrest (pulseless electrical activity and asystole), but interpreting those findings is difficult because patients who receive bicarbonate tend to have longer resuscitation times, which skews the results. Sodium bicarbonate is still used during cardiac arrest in special circumstances, such as when high potassium levels are contributing to the arrest.
Athletic Performance Booster
During high-intensity exercise lasting one to seven minutes, your muscles produce large amounts of acid as a byproduct of burning fuel without enough oxygen. This acid buildup contributes to the burning sensation and fatigue that force you to slow down. Sodium bicarbonate, taken before exercise, raises the blood’s buffering capacity, helping shuttle acid out of muscles more efficiently.
The Australian Institute of Sport recommends 200 to 400 mg per kilogram of body weight, taken with a small carbohydrate-rich meal about two to two and a half hours before exercise. For a 70 kg (154 lb) person, that works out to roughly 14 to 28 grams. At the higher end of dosing (300 to 400 mg/kg), blood buffering capacity rises enough to be performance-enhancing within two to three hours and stays elevated for three to four hours. An alternative approach involves loading over several days: 500 mg per kilogram per day, split across meals and snacks, for up to five days before competition plus the day of the event.
The main drawback is gastrointestinal distress. Nausea, bloating, and diarrhea are common at effective doses, which is why the timing and food pairing matter. Some athletes use the multi-day loading protocol specifically to avoid a single large dose that upsets the stomach.
Baking and Cooking
Baking soda is pure sodium bicarbonate, and it’s been a kitchen staple for over a century. When it contacts an acid, such as buttermilk, vinegar, lemon juice, or yogurt, it produces carbon dioxide gas. Those gas bubbles get trapped in batter or dough, causing it to rise and giving baked goods a light, fluffy texture.
This reaction starts immediately on contact, which is why recipes using only baking soda (no baking powder) need to go into the oven right away. A second wave of gas release occurs when the batter reaches temperatures above 170°F in the oven. Baking powder, by contrast, contains baking soda pre-mixed with a dry acid, so it doesn’t require a separate acidic ingredient in the recipe. Using too much baking soda without enough acid to react with leaves a soapy, metallic taste and can turn baked goods yellow.
Risks and Who Should Be Cautious
Sodium bicarbonate is roughly 27% sodium by weight, which makes it a significant source of dietary sodium even in small amounts. People with heart failure, high blood pressure, or conditions that cause fluid retention should use it cautiously if at all. In people with reduced kidney function, the extra sodium can accumulate, worsening swelling and fluid overload.
Taking too much can push blood pH too high (a condition called alkalosis), causing muscle twitching, hand tingling, nausea, and in severe cases, irregular heartbeats. It should not be used by people who are vomiting or on certain diuretics that already deplete chloride, as it can dangerously worsen the electrolyte imbalance. It can also lower calcium levels in the blood, which is particularly risky for anyone already prone to low calcium.
As an antacid, the carbon dioxide produced in the stomach can cause bloating and gas. In rare cases, taking large amounts on a very full stomach has caused stomach rupture due to rapid gas expansion, though this is exceptionally uncommon.