Around 19 percent of the U.S. population experiences constipation.1 The forceful and sometimes painful straining, as well as reduced amount of weekly bowel movements, can negatively impact your health if left untreated.
Laxatives like milk of magnesia are the first course of action for many people in treating constipation. However, I do not recommend taking laxatives, unless these are only used a last resort and with caution for a short amount of time. Your body can become dependent on laxatives if you constantly take these. Furthermore, laxatives may also decrease the colon’s ability to contract and potentially damage the large intestineoverdo’s nerves, muscles and other tissues.
What Is Milk of Magnesia?
Milk of magnesia is the branded name for magnesium hydroxide, and gets its name from its milk-like appearance. It does not contain any milk, however, as it’s an alkaline or basic suspension2 of about 8 percent magnesium hydroxide in water.3
Milk of magnesia is an oral osmotic4 that draws water into the colon from the body tissues around it, allowing stool to pass more easily. This over-the-counter (OTC) laxative is readily available without a prescription.5 Be aware that it's easy to overdose on milk of magnesia, so ONLY take as directed. Some milk of magnesia brands may also contain ingredients that are harmful for the body, such as:6,7
✓ Artificial flavoring
✓ Propylene glycol
✓ Purified water
✓ Silicone defoamer
✓ Sodium citrate
✓ Sodium saccharin
✓ Sodium salts of polymerized alkylnaphthalenesulfonic acid
✓ Sorbitol solution
✓ Xanthan gum
✓ Sodium hypochlorite (bleach)
✓ Artificial colors
I advise you to be careful when choosing laxatives like milk of magnesia and only use as a last resort, not only due to the potential side effects but also because your body may become dependent on them.8
Digestive Health Benefits of Milk of Magnesia
Milk of magnesia is known for its ability in relieving constipation and fecal incontinence, and promoting bowel movements by increasing11 water in the intestines.9 It may help get rid of flatulence as well.10 It can also work as an antacid that, when consumed in small amounts, reduces acid in the stomach.
The hydroxide ions from magnesium hydroxide combine with hydrogen ions in stomach acids to create water and eventually neutralize stomach acid. Milk of magnesia may also alleviate symptoms caused by excess stomach acid levels like heartburn, upset stomach, indigestion and other gastric problems.12,13
What Else Is Milk of Magnesia Used For?
• Skin problems: Milk of magnesia has been used by some for oily skin and as an acne treatment. When applied in small amounts, it may reduce acne-caused inflammation and assist with skin healing.
• Make-up primer: Some people have used milk of magnesia to prepare the skin for the application of other make-up products by serving as the base for their foundation.16
• Wound cleaner:17 Milk of magnesia can be used in helping treat wounds, skin rashes (like diaper rash18) and canker sores. It may act as a disinfectant to prevent skin complications, and contains healing properties that may neutralize acids and balance the skin.
• Deodorant:19 Milk of magnesia has antibacterial properties that make it hard for odor-causing bacteria to flourish.
Studies Conducted on Milk of Magnesia
Despite its popularity as a home remedy, very limited studies have been conducted about milk of magnesia. These studies also do not completely confirm the health claims that has been linked to milk of magnesia, so always proceed with caution before using this remedy. Some examples include:
• A 1975 letter published in the Archives of Dermatology cited that topical application of milk of magnesia nightly was able to help people with acne. This treatment was then paired with oral antibiotics and two washes daily using a fat-free soap, and those who tried it reported reduced redness from acne and less breakouts.20
However, there are two caveats to this. First, oral antibiotics were used to treat acne (which I do not encourage in any way), and second, this wasn’t a formal study. If you’re thinking about using milk of magnesia for healing skin conditions, talk to a dermatologist or health expert first.
• Another type of laxative called polyethylene glycol 3350 without electrolytes was compared with milk of magnesia for their effects on children with constipation and fecal incontinence. The researchers discovered that while both laxatives were effective in treating these conditions, polyethylene glycol 3350 was better well-received compared to milk of magnesia.21
This was done as a randomized, prospective and comparison study conducted among 79 children, and the results were published in the journal Pediatrics in 2006.
The researchers sought to evaluate both these laxatives’ efficacy, safety, acceptance and one-year outcomes. The children in the study were assigned to randomly receive either of the two laxatives (39 received polyethylene glycol, while 40 received milk of magnesia).
The children were evaluated as improved or recovered depending on resolution of constipation, fecal incontinence and abdominal pain after one, three, six and 12 months. During each follow-up visit, both groups of children had increased frequency of bowel movements, decreased frequency of episodes of incontinence and resolved abdominal pain. After the study period, results showed that:
◦ A 95 percent compliance rate was recorded among those who took polyethylene glycol, while there was a 65 percent compliance rate for children who took milk of magnesia.
◦ After 12 months, 62 percent of children who took polyethylene glycol and 43 percent of children who took milk of magnesia showed improvement.
◦ Around the same time frame, 33 percent of polyethylene glycol-treated children and 23 percent of milk of magnesia-treated children eventually recovered.
• An anti-flatulence diet combined with milk of magnesia laxative was not able to significantly reduce the initial rectal area or intrafraction prostate motion, among subjects voiding their rectum before imaging, as highlighted in a study published in the International Journal of Radiation Oncology, Biology Physics in 2010.22
The 42 patients with T1c-T2c prostate cancer in the study voided their bladder and rectum prior to three magnetic resonance imaging (MRI) scans that were obtained every nine seconds for nine minutes in a vacuum immobilization device.
Milk of Magnesia Dosage Levels
Milk of magnesia is available either as a liquid or a tablet. A bowel movement should then occur within half an hour up to six hours after intake.23 To get its laxative effects, the typical milk of magnesia dosage for adults and children aged 12 years old and above is 2 to 4 tablespoons once a day, preferably before bedtime. This should be followed by drinking a full glass (8 ounces) of water.
To address indigestion, adults and children aged 12 years old and above must take 1 to 3 teaspoons, up to four times a day. milk of magnesia tablets, the dosage tends to vary per age, and it's listed on the product label. When taking milk of magnesia, either as a liquid, capsule or chewable tablet, take note of these reminders:24
✓ Follow your doctor’s orders, especially when it comes to dosage and schedule of intake.
Avoid intake of more medicine than what is prescribed and refrain from taking it more often than when the doctor tells you.
✓ If you miss a milk of magnesia dose recommended by your doctor, take it as soon as you remember.
However, if it’s nearly time for the next dose, skip the missed dose and follow your regular schedule. NEVER double up on doses.
Ideally, you should refrain from taking any type of laxative for longer than a week. These can be habit-forming and may harm the bowels if used for too long or too often.
✓ Follow the instructions on the medicine label if you are taking milk of magnesia without a prescription.
✓ Drink enough liquid if you’re using milk of magnesia as a laxative.
✓ Shake the bottle well before using. Make sure to measure the oral liquid medicine with a marked measuring spoon or medicine cup.
✓ If taking chewable tablets, chew them completely before swallowing.
If you below to any of the following groups of people, talk to a doctor or health expert first prior to taking milk of magnesia, because there might be complications that could follow after taking it:25
- People with kidney disease or kidney problems (because they wouldn’t be able to tolerate excess magnesium, and increased magnesium levels can overwhelm the body and lead to magnesium toxicity26)
- People on a magnesium-restricted diet
- People taking prescription drugs (because of possible interactions)
- Pregnant or breastfeeding women (talk to your OB-GYN first about taking any type of laxative)
Furthermore, if you constantly need milk of magnesia to prompt bowel movement or are already taking it but aren’t seeing results, talk to a doctor. Milk of magnesia serves as a short-term treatment, and in this case, this might be a sign that you have an underlying medical condition.
Store milk of magnesia in a closed container at room temperature, and keep it out of children’s reach. Do not expose it to heat, moisture and direct light, and do not freeze it. Never share your medicine with anyone as well.27 Never use old and expired milk of magnesia, and dispose of it accordingly. Consult a pharmacist, physician or health expert on the best way to dispose of leftover medicine after finishing your treatment.
Milk of Magnesia’s Side Effects
Because milk of magnesia is a laxative, one of its side effects is diarrhea, which is why you must follow the recommended dose to promote normal bowel movement. While an appropriate dose can still lead to loose stools, this is just a temporary side effect.28 On the other hand, if these severe side effects arise after taking milk of magnesia, consult your doctor immediately:29,30,31
✓ Rectal bleeding
✓ Upset stomach
✓ Allergic reactions like itching or hives, swelling of the face or hands, swelling or tingling in mouth or throat, chest tightness and/or trouble breathing
As mentioned earlier, increased milk of magnesia intake was linked to the colon’s reduced ability to contract, and wreak havoc on the large intestine’s nerves, muscles and tissues, which may even worsen constipation over time. Ideally, use milk of magnesia on a short-term basis only to treat occasional constipation.32
If your physician recommends that you take milk of magnesia, it's important to talk about other drugs you are currently taking. Milk of magnesia is known to interact with other OTC medicines, prescription and non-prescription drugs, herbal remedies and dietary and nutritional supplements. It can interfere with the absorption of other medicines as well, such as:33,34
✓ Dasatinib (Spyrcel)
✓ Delavirdine (Rescriptor)
✓ Digoxin (Digox or Lanaxin)
✓ Phosphate supplements like potassium phosphate
✓ Tetracycline antibiotics like doxycycline and minocycline
✓ Quinolone antibiotics like ciprofloxacin or levofloxacin
✓ Azole antifungals like ketoconazole and itraconazole
Milk of magnesia is one example of a home remedy that can be potentially useful for multiple health issues. However, remember that natural methods should still be your first choice of treatment for certain conditions like constipation. After all, milk of magnesia is not a “magic solution” that’ll address diseases, and so much still has to be researched and concluded about its benefits.
Natural Remedies to Try If You’re Constipated
Constipation is a temporary and relatively easy-to-resolve condition that doesn’t require the use of laxatives. Instead of relying on these drugs, take note of these natural remedies and techniques that work in alleviating constipation:
✓ Remove gluten sources from your diet: Eating too much gluten-rich foods can lead to the formation of a glued-together lump in your gut that can prevent proper digestion and eventually result in constipation.
Wheat, barley, rye, spelt and other grains are common sources of gluten.
✓ Increase intake of naturally fermented foods: These can improve your intestinal flora and increase the amount of good bacteria in your body.
Sauerkraut, pickles, kimchi, natto and kefir (if you can tolerate dairy) are good examples of naturally fermented foods.
If you suspect that you’re not getting enough beneficial bacteria from your diet alone, you can take a high-quality probiotic supplement.
✓ Focus on eating a whole-food diet: This means consuming high amounts of fresh and organic fruits and vegetables that deliver fiber and other beneficial nutrients.
Ideally, you should get most of your fiber from various vegetables, and not grains.
✓ Add more fiber sources to your meals: Aside from eating fresh and organic fruits and vegetables, organic psyllium husk and freshly ground organic flax seed (shoot for 35 grams daily) are other vital fiber sources that can assist with preventing constipation.
✓ Drink high-quality, filtered water: This helps flush out the toxins in your body that can contribute to constipation.
✓ Squat instead of sit to move your bowels: Squatting straightens your rectum, relaxes your puborectalis muscle and promotes complete emptying of your bowel, minus the straining.
Plus, squatting has been scientifically shown to help relieve constipation and hemorrhoids.
✓ Address emotional challenges: Tools like the Emotional Freedom Techniques (EFT) may help with emotional problems you may encounter if you’re constipated.
✓ Make it a point to exercise daily: Regular exercise is said to aid with lowering the risk for constipation.35
On the other hand, avoid these items as much as possible if you’re treating constipation and/or preventing future instances of this condition:
• Artificial sweeteners, excess sugar (especially fructose), chemical additives, monosodium glutamate, excessive amounts of caffeine and processed foods: All of these are detrimental to your gastrointestinal and immune function.
• Pharmaceutical drugs such as painkillers (codeine or hydrocodone): These medicines can slow down your bowel function if taken excessively.
• Antidepressants and antibiotics: These can lead to various gastrointestinal disruptions.
Frequently Asked Questions About Milk of Magnesia
Q: What does milk of magnesia do?
Q: How does milk of magnesia work in the body?
A: Milk of magnesia works by drawing water to the bowel from the nearby tissue surrounding it, resulting in softening of stool and promoting bowel activity.39 If it’s used as antacid, milk of magnesia can help decreases the amount of stomach acid, which helps address the gastrointestinal problems.40,41
Q: Is milk of magnesia safe to take during pregnancy?
A: If you’re a pregnant woman who wishes to take milk of magnesia to resolve constipation, talk to your OB-GYN first before taking any type of laxative.
Q: What are the milk of magnesia dosages?
A: It depends on the patient’s age and the condition that requires milk of magnesia. If you’re taking milk of magnesia as a laxative, the dosage should be as follows:42
Adults 12 years old and above
2 to 4 tablespoons once a day (preferably at bedtime), followed by a full glass (8 ounces) of water
If milk of magnesia is being used a treatment for indigestion, the dosage should be:
Adults 12 years old and above
1 to 2 tablespoons, up to four times a day
To be determined by a doctor or physician
In general, if children (especially those below 6 years old) need to take milk of magnesia in liquid or tablet form, consult with a physician first to determine whether they can take this particular laxative.
Q: How long does milk of magnesia take to work?
A: It can take up to six hours before milk of magnesia kicks in. Within this period, expect bowel movement already. In some cases, bowel movement may already occur within half an hour. In a nutshell, the nature and the cause of constipation can play a role in how long it will take for milk of magnesia to work on the body.43
Q: What happens if you take too much milk of magnesia?
A: Increased intake of milk of magnesia can lead to side effects like an upset stomach, stomach cramps, vomiting and diarrhea.44 In some cases, people may also experience allergic reactions like itching or hives, swelling of certain body parts, chest tightness, breathing difficulties, rectal bleeding and blood in stools.45 If any of these side effects occur, stop taking milk of magnesia immediately.