What Exactly Is Epsom Salt, and How Is It Different from Regular Table Salt?

What Exactly Is Epsom Salt, and How Is It Different from Regular Table Salt?

Reading time: about 9 minutes | Last updated: October 2026 | Category: Explainers, Wellness, Home Remedies

Quick Answer: What Is Epsom Salt?

Epsom salt is the common name for magnesium sulphate heptahydrate (MgSO4·7H2O), a mineral compound made of magnesium, sulphur, and oxygen that forms small, colourless crystals. It is used mainly for baths, foot soaks, gardening, and in some medical settings. Regular table salt is sodium chloride (NaCl), a completely different compound used for seasoning and preserving food. Despite the name, Epsom salt is not really a salt in the kitchen sense, it is not meant for cooking, and it tastes bitter. The two should never be swapped.

Key Takeaways

• Epsom salt = magnesium sulphate. Table salt = sodium chloride.
• Epsom salt is bitter and used for baths, soaks, and horticulture, not for seasoning food.
• Table salt supplies sodium and chloride, which the body needs in small amounts, while Epsom salt supplies magnesium and sulphate.
• Swallowing Epsom salt can act as a strong laxative and can be unsafe without medical guidance.
• In India, look for pharmaceutical (IP or BP) grade magnesium sulphate if you plan to use it on skin.

What Is Epsom Salt? A Simple Explanation

Epsom salt is a naturally occurring mineral compound. It dissolves quickly in water and releases magnesium ions and sulphate ions. The name comes from Epsom, a town in Surrey, England, where in the early 1600s a farmer reportedly noticed that water from a local spring tasted bitter and seemed to soothe skin and aches. The mineral-rich water became famous, and the crystals that were later extracted from it were named after the town.

Today, most commercial Epsom salt is made in factories by reacting magnesium-containing minerals with sulphuric acid, or it is extracted from natural mineral deposits and brines. Pure, bath-grade or pharmaceutical-grade crystals are processed and tested for purity.

The Chemistry in Plain Language

Chemical name: Magnesium sulphate heptahydrate Chemical formula: MgSO4·7H2O Appearance: White or colourless crystals that look like coarse salt or sugar Taste: Bitter and unpleasant Solubility: Dissolves readily in warm water

The "heptahydrate" part means each unit of magnesium sulphate holds seven molecules of water in its crystal structure. The anhydrous form (without water) is also used in industry and as a drying agent in laboratories.

What Is Table Salt?

Table salt is sodium chloride (NaCl). It is made from rock salt mined underground or from evaporated seawater. Most table salt sold in India is iodised, meaning potassium iodate or potassium iodide is added to prevent iodine deficiency and goitre. Salt is essential in small amounts for fluid balance, nerve function, and muscle contraction, but excess sodium raises blood pressure and the risk of heart disease.

Epsom Salt vs Table Salt: Side-by-Side Comparison

Key Differences Explained

1. Different Chemical Makeup

This is the core difference. Epsom salt contains magnesium and sulphate. Table salt contains sodium and chloride. The body treats them very differently.

2. Different Taste and Use

Table salt is a seasoning and preservative. Epsom salt is bitter and not used in cooking. It is bought from pharmacies, wellness stores, and garden suppliers instead of the kitchen aisle.

3. Different Effects on the Body

Sodium and chloride regulate fluid and nerve activity. Magnesium plays a role in muscle relaxation, energy, and hundreds of enzyme reactions. Sulphate is involved in various metabolic processes. When Epsom salt is swallowed, it draws water into the intestines, which causes a laxative effect.

4. Different Crystal Appearance

Epsom salt crystals often look like small, elongated, glassy rods or needles, whereas table salt usually has tiny cubic grains. Appearance alone is not a reliable way to identify a product, so always read the label.

5. Different Safety Considerations

Table salt in excess affects blood pressure. Epsom salt in excess, particularly by mouth, can cause diarrhoea, dehydration, and in people with kidney problems, dangerously high magnesium levels. Neither should be used carelessly.

Common Uses of Epsom Salt

In the Bath and Foot Soak

The most popular use. People add 1 to 2 cups to a warm bath or 1/2 cup to a foot soak to relax muscles, ease tired feet, soften skin, and unwind. Evidence that magnesium absorbs through skin is limited, but the warm water and ritual are soothing.

As a Compress

Dissolved in warm water, it is used on a cloth for sore areas.

In Gardening

Gardeners use Epsom salt as a source of magnesium and sulphur for plants. It is sometimes applied to tomatoes, peppers, roses, and other plants showing magnesium deficiency (yellowing between leaf veins). A common home mix is about 1 tablespoon per litre of water as a foliar spray or soil drench, but a soil test is the best guide, since too much can harm soil balance.

As a Mild Skin Exfoliant

Mixed with oil, it can gently scrub rough areas such as heels and elbows. It should not be used on broken skin or on the face.

In Medicine (Under Professional Supervision)

Magnesium sulphate is also an established medicine, covered in detail in our separate article. Hospitals use injectable magnesium sulphate for conditions such as severe pre-eclampsia and eclampsia and for certain heart rhythm and magnesium-deficiency problems. As an oral laxative, it is used short term under medical advice. These uses involve exact doses and monitoring and are very different from home bathing.

Other Household and Industrial Uses

Magnesium sulphate is used in some fertilisers, in textiles and dyeing, in leather tanning, in certain food and brewing processes where approved, and as a drying agent in laboratories.

Common Uses of Table Salt

• Seasoning and flavouring food
• Preserving foods such as pickles (achar), fish, and meat
• Providing iodine when iodised
• Gargling for sore throat and nasal rinses (with correct preparation)
• Making brine and in some cleaning uses

Can You Use Epsom Salt Instead of Table Salt (or Vice Versa)?

No. They are not interchangeable.

• Epsom salt in cooking would taste very bitter and could cause diarrhoea and stomach upset.
• Table salt in an Epsom bath is a different experience. It can be soothing for feet in a traditional way, but it does not contain magnesium sulphate, so it will not give the same effect.
• Rock salt (sendha namak) is also sodium chloride with trace minerals. It is not the same as Epsom salt either.

Epsom Salt vs Rock Salt vs Sea Salt vs Himalayan Pink Salt

All sodium chloride salts act in similar ways in the body. Epsom salt stands apart because it is magnesium sulphate.

Is Epsom Salt Really a "Salt"?

In chemistry, a salt is any compound formed when an acid reacts with a base, made up of positive and negative ions. By that definition, magnesium sulphate is indeed a salt. In everyday language, "salt" means sodium chloride. That is why Epsom salt is a chemical salt but not a kitchen salt. The confusion comes from the shared word, not from similarity in function.

What Does Epsom Salt Do to the Body?

When dissolved in a bath, Epsom salt gives you warm, mineral-rich water that relaxes muscles and calms the mind. The part about magnesium passing through skin to boost your levels is debated and unproven in strong studies. When swallowed, magnesium sulphate is poorly absorbed and works as an osmotic laxative, pulling water into the gut.

Safety Basics

Do:

• Use it as directed on the label for baths and soaks
• Choose bath-safe or pharmaceutical-grade products
• Keep it away from children and pets
• Store in a cool, dry place, in a labelled airtight container

Don't:

• Swallow it unless a doctor advises
• Use it on broken or infected skin
• Use it if you have kidney disease without medical advice
• Use agricultural or industrial grade for body use
• Use it as a replacement for medical care

Seek medical help urgently if someone swallows a large amount and develops vomiting, severe diarrhoea, weakness, slow breathing, or confusion.

How to Tell Genuine Epsom Salt from Fake or Low-Quality Products

• Read the label for "magnesium sulphate" or "magnesium sulfate heptahydrate" with the formula MgSO4·7H2O.
• Look for IP, BP, or USP grade for products meant for skin or medical use.
• Check for batch number, manufacturing and expiry dates, manufacturer details, and a proper brand.
• Choose reputable sellers on e-commerce platforms with verified reviews, and compare with pharmacy stock.
• Be wary of unlabelled bags, very low prices, or products that smell strange or look clumpy and dirty.
• Remember that bitter taste can identify it, but never taste-test an unknown powder.

Quick Facts About Epsom Salt

• First discovered in Epsom, England, in the 17th century
• Chemically called magnesium sulphate heptahydrate
• Dissolves in water, giving a clear solution
• Bitter taste
• Used externally in baths, foot soaks, and compresses
• Used in gardening and some industries
• Medicinal forms are used only under professional supervision
• Not iodised and not for cooking

Frequently Asked Questions

What is Epsom salt?

Epsom salt is magnesium sulphate, a mineral compound that forms small white crystals and dissolves in water. It is used mostly in baths, foot soaks, and gardening.

Is Epsom salt the same as table salt?

No. Epsom salt is magnesium sulphate. Table salt is sodium chloride. They have different chemistry, taste, uses, and effects on the body.

Can I use Epsom salt in cooking?

No. It is bitter and acts as a laxative when swallowed.

Is Epsom salt the same as rock salt (sendha namak)?

No. Rock salt is sodium chloride, while Epsom salt is magnesium sulphate.

Why is it called Epsom salt?

It is named after Epsom, a town in England where a bitter, mineral-rich spring was discovered in the 1600s.

Is Epsom salt safe on the skin?

For most healthy people, yes, when dissolved in warm water and used as directed. Avoid broken or infected skin and ask a doctor if you have kidney disease, heart problems, or diabetes.

Can Epsom salt be used on plants?

Yes, in small amounts, mainly to correct magnesium deficiency. Over-use can harm soil, so test first if possible.

Does Epsom salt contain sodium?

No, it does not contain sodium. It contains magnesium and sulphate.

Is Epsom salt a medicine?

Pharmaceutical-grade magnesium sulphate is used as a medicine in specific settings, always under professional supervision. Home bath crystals are a wellness product.

How should I store Epsom salt?

Keep it dry, sealed, and out of children's reach, because damp conditions make crystals clump.

The Bottom Line

Epsom salt and table salt share a word and a crystalline look, but that is where the similarity ends. Epsom salt is magnesium sulphate, valued for soaks, baths, gardening, and, in controlled doses, medicine. Table salt is sodium chloride, valued for food. Knowing the difference helps you buy the right product, use it safely, and avoid common mistakes.

Disclaimer: This article is for general information only and is not medical advice. Consult a qualified professional before using any substance for health purposes.