Does milk of magnesia expire?

In this brief article, we will answer the question: does milk of magnesia expire, its benefits and side effects. We will also explain the side effects of consuming expired milk of magnesia

Does milk of magnesia expire?

Yes, milk of magnesia does expire. According to HPRA, milk of magnesia is only safe to use within the first six months of opening. Furthermore, unlike other products that stay safe for consumption even after their expiry date, milk of magnesia does not remain safe. It should not be consumed after its mentioned expiry date has passed.

When does milk of magnesia expire? 

Milk of magnesia does come with an expiry date mentioned on the label. If you are still unsure, the rule of thumb is to consume Milk of Magnesia within 6 months of its opening. It usually takes 6 hours to stimulate bowel movements. 

Does milk of magnesia need to be refrigerated? 

No, it is strongly advised not to refrigerate milk of magnesia. Simply store it at room temperature after tightly securing the cap. Freezing milk of magnesia is also recommended and both these storage methods should be avoided at all times.

Is expired milk of magnesia safe to consume? 

Milk of Magnesia is a special suspension and should not be consumed after its expiry. It’s expiry date is mentioned on the label and one should not use it after the expiry date has passed.

What is milk of magnesia?

Milk of magnesia is a hydrated suspension of magnesium carbonate in water, it is called magnesium hydroxide. It is an inorganic compound which is found naturally as a mineral brucite. It is white in color and usually used as an antacid or laxative.

Milk of magnesia is used in many medicines and is used to cure constipation. It is a laxative and helps cause movements in intestines, which helps cure constipation. It is also used in case of heartburn, to treat upset stomach and to cure indigestion.

How to use milk of magnesia?

Milk of magnesia is present in many antacids and laxatives found in the market. It is in the form of chewable tablets and you can chew it before swallowing. If you want to consume it in liquid form, make sure to shake the bottle as it is a suspension.

When taking medicine in a prescribed dose it is better to use measuring cups that come with medicine. Using tablespoons may mess with the required dosage of milk of magnesia. Also don’t drink too much as it is a laxative.

Benefits of Milk of magnesia:

Milk of magnesia is very good as a medicine in case of constipation. It is made of inorganic components and hence doesn’t affect the body so much. It also has laxative properties which relaxes the intestine muscle when consumed.

Milk of magnesia is used as an antacid in case of heartburn and indigestion. Antacids are alkaline chemicals which lower the acidity of the stomach. When milk of magnesia reaches stomach it neutralizes the acid and reduces the effect of heartburn

It is used to cure stomach disturbance or indigestion, a condition where you can’t digest food. As it is an antacid it maintains the pH of the stomach while relaxing the muscle. In this way it helps with indigestion and other digestive problems

Side effects of using milk of magnesia:

Just like the benefits milk of magnesia also has side effects on health and body. Some of these side effects are:


Milk of magnesia is a laxative and is consumed to cure constipation. But if consumed in excess amount it can cause diarrhea too. If diarrhea persists it is better to consult a doctor because it is dangerous for your health.

Excess magnesium in body:

Another side effect of consuming too much milk of magnesia is rise in magnesium level in blood. Symptoms of high level of magnesium in blood are muscle weakness, irregular breathing, shallow breath, mood changes and irregular heartbeats


Due to an increase in mineral content in the body and self-induced diarrhea, you might suffer from dehydration. The symptoms of dehydration because of milk of magnesia are dry mouth, dizziness, extreme thirst, decreased urination and muscle fatigue.

Upon consumption of milk of magnesia, a severe allergic reaction may occur in some people but is very rare. Some people also become dependent on it to pass a stool and excess consumption also causes abdominal pain, bloody stools and rectal bleeding

Other FAQs about Milk which you may be interested in.

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Expiration of milk of magnesia:

Milk of magnesia is a naturally occurring compound but to make it edible it needs processing. Processed milk of magnesia expires and loses its effect. It is better not to consume an expired product as it is no longer effective.

If expired milk of magnesia is consumed the side effects that happen are:


A long lasting diarrhea or upset stomach after consuming an expired laxative is very common

Stomach cramps:

As it is antacid in nature, one effect it may have on the stomach is relaxing the muscle while neutralizing the acid. If expired medicine is in stomach it may affect body’s natural flora and causes health problem

Chalky taste in mouth:

Unlike good milk of magnesia, bad milk of magnesia leaves a chalky taste in the mouth and induces gag reflex when consumed. You can identify if medicine is expired by its taste and smell

Nausea and Vomiting:

When a product expires the microbes of the surrounding grow in it. If expired medicine is consumed there is a chance that it has bacteria. These bacteria make you sick and affect your overall health.

These symptoms may become intense depending on your health and how much expired milk of magnesia you consume. A bottled milk of magnesia only goes bad if exposed to air bacteria, otherwise it is safe to consume before expiration.


In this brief article, we have answered the question: does milk of magnesia expire, its benefits and side effects. We have also explained the side effects of consuming expired milk of magnesia