What Salt Is Good for Constipation? Understanding Your Options

December 1, 2025 •

3 min read

Approximately 16 out of 100 U.S. adults experience symptoms of constipation, and many seek relief with natural remedies. While regular table salt is not the answer, specific magnesium-based salts have proven osmotic laxative properties that can help, provided they are used correctly.

Quick Summary

Specific magnesium-based salts like citrate, oxide, and sulfate are effective osmotic laxatives for occasional constipation. They draw water into the intestines to soften stool and stimulate bowel movements, with each type varying in absorption and use. Oral administration of food-grade magnesium salt is key for efficacy.

Key Points

Magnesium salts are effective for constipation: Not table salt, but magnesium-based salts like citrate, oxide, and sulfate act as osmotic laxatives.
Magnesium citrate is fast and potent: This type is highly absorbed and quick-acting, often used for occasional relief and bowel preparation.
Oral Epsom salt is a viable laxative: Food-grade Epsom salt (magnesium sulfate) dissolved in water is FDA-approved for occasional constipation and works within 30 minutes to 6 hours.
Absorption varies by type: Magnesium oxide is absorbed less readily than citrate, which can make it a slower-acting yet effective option.
Bath soaks are not a proven constipation cure: While relaxing, there is little scientific evidence that magnesium is absorbed through the skin from Epsom salt baths in quantities sufficient to relieve constipation.
Use with caution and only for the short term: Avoid long-term dependency on these salts and consult a doctor, especially for chronic constipation or other health conditions.
Hydration is critical: Drinking plenty of water is essential when using any magnesium laxative to ensure it works effectively and to prevent dehydration.

Most people associate the word 'salt' with table salt (sodium chloride), but this is not the type of salt used to treat constipation. When referring to this remedy, experts are talking about magnesium-based salts, which act as osmotic laxatives. These compounds work by drawing water into the intestines through osmosis, which helps soften the stool and stimulates intestinal contractions to promote a bowel movement. This article details the different types of magnesium salts, their specific uses for constipation, and essential safety precautions.

Understanding Different Types of Magnesium Salts for Constipation

Magnesium Citrate

This form of magnesium combines with citric acid and is a popular choice for constipation due to its rapid absorption. It's available in various forms and is effective for short-term relief, often working within 30 minutes to 6 hours.

Magnesium Oxide

Magnesium oxide is a common and affordable magnesium salt found in products like Milk of Magnesia. It's not absorbed as easily as magnesium citrate, making it a slower-acting laxative but still effective. While less likely to cause high blood magnesium levels due to its lower absorption, it can still cause digestive issues.

Epsom Salt (Magnesium Sulfate)

Epsom salt is magnesium sulfate and is FDA-approved as an oral laxative when dissolved in water. Using a food-grade variety orally helps draw water into the intestines to soften stools, typically producing a result within 30 minutes to six hours. While Epsom salt is popular for relaxing baths, this method is not effective for constipation as significant magnesium absorption through the skin for this purpose is unproven.

Guidelines for Using Magnesium Salts

For safe and effective use of magnesium salts for constipation, follow these general guidelines:

Read the label: Always follow the specific dosage instructions on the product label.
Hydrate adequately: Drink a full glass of water with each dose.
Limit use: Only use for occasional constipation and not for more than a week without consulting a doctor.
Add flavor: Adding lemon juice can help with the taste of Epsom salt in water.

Comparison of Magnesium Salts for Constipation


Feature	Magnesium Citrate	Magnesium Oxide	Epsom Salt (Magnesium Sulfate)
Absorption	Very good absorption rate	Lower absorption rate	Poorly absorbed when ingested orally
Speed of Action	Fast-acting (30 mins - 6 hours)	Slower-acting	Fast-acting (30 mins - 6 hours)
Potency	Potent osmotic laxative	Effective osmotic laxative	Effective osmotic laxative
Primary Use	Occasional constipation, bowel prep	Occasional constipation, antacid	Occasional constipation (oral), bath soak (topical)
Side Effects	Bloating, gas, diarrhea, cramping	Bloating, gas, diarrhea, cramping	Bloating, diarrhea, abdominal cramps
Availability	Liquid, powder, tablet	Tablet, capsule, liquid (Milk of Magnesia)	Powder, typically for oral or topical use

Important Safety Considerations and Precautions

Magnesium salts are generally safe for short-term use, but precautions are necessary. Consult a healthcare professional before use, especially with conditions like kidney disease, heart problems, or if taking other medications, as magnesium can interact and high levels can be dangerous. Do not use if experiencing severe abdominal pain, nausea, or vomiting. Symptoms of magnesium overdose can include altered mental status, slow heartbeat, and muscle weakness. Discontinue use and seek medical attention if you experience rectal bleeding or no bowel movement after two doses.

Conclusion: Choosing the Right Salt for Your Needs

Magnesium citrate, magnesium oxide, and food-grade Epsom salt are options for occasional constipation, working by drawing water into the colon to soften stools. Magnesium citrate is often the quickest, while magnesium oxide is milder. The best choice depends on personal needs and medical advice. These should not be used long-term; chronic constipation requires addressing underlying causes. A high-fiber diet, adequate hydration, and exercise are crucial for prevention.

For specific information on magnesium sulfate, consult resources like the DailyMed database

Frequently Asked Questions

No, regular table salt (sodium chloride) is not used for constipation. Specific magnesium-based salts, which act as osmotic laxatives, are the ones recommended for relief.

Magnesium citrate is often considered one of the most effective and fast-acting options for occasional constipation due to its high absorption rate. However, magnesium oxide and Epsom salt are also effective choices, and the best option depends on individual needs and a doctor's advice.

There is no strong scientific evidence that an Epsom salt bath provides significant constipation relief. While relaxing, not enough magnesium is absorbed through the skin for a laxative effect. Oral ingestion of food-grade Epsom salt is the proven method.

When taken orally, food-grade Epsom salt typically produces a bowel movement within 30 minutes to 6 hours. The effect can vary based on the individual.

Magnesium citrate is intended for occasional, short-term constipation relief, not chronic use. Long-term dependence on laxatives can be detrimental to bowel function. For chronic constipation, consult a doctor to address underlying causes.

The main risks of using magnesium salts include potential side effects like bloating, cramping, and diarrhea. Overdosing can lead to hypermagnesemia (high magnesium levels), especially in individuals with kidney disease. Always follow dosage instructions and consult a doctor.

It is recommended to drink a full glass (8 ounces) of water or liquid with each dose of a magnesium salt laxative. This aids the laxative's osmotic action and helps prevent dehydration.