Many people use Milk of Magnesia as an antacid to relieve symptoms of acid reflux, heartburn, and indigestion. However, there is some confusion around whether Milk of Magnesia itself is acidic or basic. In this article, we will delve into the science behind Milk of Magnesia and find out its true nature.
What is Milk of Magnesia?
Milk of Magnesia is a milky white suspension containing magnesium hydroxide (Mg(OH)2) in water. It has a slightly sweet taste and is commonly used as an antacid to neutralize stomach acid and relieve symptoms of acid reflux, heartburn, and indigestion. It is also used as a laxative to relieve constipation.
What is pH?
pH is a measure of the acidity or basicity of a solution. It is a logarithmic scale that ranges from 0 to 14. A solution with a pH of 0 is highly acidic, while a solution with a pH of 14 is highly basic. A solution with a pH of 7 is considered neutral, neither acidic nor basic.
Is Milk of Magnesia acidic or basic?
Milk of Magnesia is a basic (alkaline) solution with a pH of around 10.5. This means that it has more hydroxide ions (OH-) than hydrogen ions (H+), making it a base. When Milk of Magnesia is ingested, it neutralizes the excess acid in the stomach by reacting with it to form magnesium chloride (MgCl2) and water (H2O).
Mechanism of Action
When Milk of Magnesia is ingested, it reacts with stomach acid (hydrochloric acid, HCl) to form magnesium chloride and water according to the following equation:
Mg(OH)2 + 2HCl → MgCl2 + 2H2O
This reaction neutralizes the acid, raising the pH of the stomach and relieving the symptoms of acid reflux, heartburn, and indigestion.
Milk of Magnesia as a Laxative
Milk of Magnesia is also used as a laxative to relieve constipation. When ingested, it attracts water from the surrounding tissues into the colon, softening and increasing the size of the stool. This makes it easier to pass the stool and relieves constipation.
Milk of Magnesia is generally safe when used as directed. However, it can cause some side effects, such as:
- Abdominal cramps
If you experience any of these side effects, stop taking Milk of Magnesia and consult your doctor or pharmacist.
Milk of Magnesia vs. Other Antacids
There are many other antacids available on the market, such as Tums, Rolaids, and Maalox. These antacids work by neutralizing stomach acid with the help of different active ingredients, such as calcium carbonate, aluminum hydroxide, and magnesium hydroxide.
Compared to other antacids, Milk of Magnesia has some unique advantages:
- It has a longer duration of action, up to 8 hours
- It has a mild laxative effect, which can be beneficial for people with constipation
- It does not contain aluminum, which can cause constipation and other side effects in some people
- It has a mild taste and is easy to swallow
Table 1 – Comparison of Milk of Magnesia and Other Antacids
|Milk of Magnesia||Tums||Rolaids||Maalox|
|Active Ingredient||Magnesium Hydroxide||Calcium Carbonate||Calcium Carbonate, Magnesium Hydroxide||Aluminum Hydroxide, Magnesium Hydroxide, Simethicone|
|Duration of Action||Up to 8 hours||2-3 hours||2-3 hours||3-4 hours|
In conclusion, Milk of Magnesia is a basic (alkaline) solution with a pH of around 10.5. It works as an antacid by neutralizing stomach acid, and as a laxative by attracting water into the colon. Compared to other antacids, it has a longer duration of action, a mild laxative effect, no aluminum content, and a mild taste, making it a popular choice among consumers. However, it can cause some side effects, such as diarrhea, abdominal cramps, nausea, vomiting, and dehydration. If you experience any of these side effects, stop taking Milk of Magnesia and consult your doctor or pharmacist.
Frequently Asked Questions
- Q: Is Milk of Magnesia an acid?
- A: No, Milk of Magnesia is a basic (alkaline) solution with a pH of around 10.5.
- Q: Does Milk of Magnesia contain aluminum?
- A: No, Milk of Magnesia does not contain aluminum.
- Q: How long does Milk of Magnesia last?
- A: Milk of Magnesia can last up to 8 hours.
- Q: Can Milk of Magnesia cause diarrhea?
- A: Yes, Milk of Magnesia can cause diarrhea as a side effect.
- Q: Can Milk of Magnesia be used during pregnancy?
- A: It is best to consult with a doctor before using Milk of Magnesia during pregnancy.
- National Center for Biotechnology Information. PubChem Compound Summary for CID 14801, Magnesium hydroxide. https://pubchem.ncbi.nlm.nih.gov/compound/Magnesium-hydroxide
- University of Wisconsin-Madison Chemistry Department. Acid-Base Titrations. https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/Supplemental_Modules_(Analytical_Chemistry)/Quantitative_Analysis/Gravimetric_Analysis/Acid-Base_Titrations
- US National Library of Medicine. Magnesium hydroxide. https://medlineplus.gov/druginfo/meds/a601116.html