Relieving Constipation

By Fritz Mequiabas, RN,  BSN

Relieving constipation

Are you looking for some quick relief for constipation? There are numerous types of laxatives available that can do the job.

Each category of laxative works in a different way. Before choosing one, you should know that some types of laxatives promote dependency and a decrease in bowel function. 

This article discusses the various types of laxatives, looking at both positive and negative attributes. Our goal is to help you to choose which laxative is right for you.

A Look at Laxatives

Laxatives are widely used for relieving constipation and are usually available without a prescription.

They can induce bowel movements or loose hardened stools, and are especially valuable if constipation persists for a longer period of time.

Osmotic laxatives

Osmotic laxatives work by causing the intestines to absorb in water from surrounding body tissue.

The un-absorbed saline ions find their way to the intestines, where they draw in water and soften stool. If too much water is pulled in it can cause diarrhea, which may result in dehydration and an electrolyte imbalance.

Bloating and cramping are also common side effects, due to gas build-up while the laxative is working. 

Examples of osmotic laxatives are Epson Salt, Lactulose, Sorbitol, Polyethylene glycol compounds and Magnesium hydroxide (Milk of Magnesia).

These osmotic laxatives are only for occasional use, since there is a danger for mineral toxicity when they are used too much. Those with kidney disease should only take an osmotic laxative if instructed to do so by their doctor.

A magnesium supplement may be able to help eliminate constipation with doses as low as 200 to 400 mg. Through the osmotic action of pulling extra water into the colon, the magnesium helps to make stool soft and slippery.

Magnesium supplements are not only for constipation but for the overall health.

It supports muscle and nerve function, increases energy and boosts the immune system. 

Emollient laxatives (stool softeners)

Stool softeners contain a docusate compound, which is a wetting agent that enhances the penetration of water into stool.

As moisture in the stool is increased, it softens the stool and helps it to pass more quickly through the colon.

Some studies have shown that stool softeners are not very consistent in relieving constipation, may require as much as a week to relieve constipation. If after a week there is no relief, then the dosage is increased.

Docusate is generally safe for short-term use. However, it can cause an increase in the absorption of medications and mineral oil by the intestines, so it should only be used occasionally.

Individuals who are pregnant, have a heart condition, hemorrhoids or anal fissures can benefit the most from stool softeners, as they help to reduce straining. Continued use may cause an imbalance in electrolytes.

Bulk forming laxatives

Bulk forming laxatives work by increasing the amount of fiber in the stool. Fiber helps to hold moisture in the stool, plus it causes stool to be more bulky.

This bulk is what stimulates peristalsis, the wave-like contractions of the colon that moves waste along. Without bulky stool, the stool tends to stay longer in the colon, resulting in it drying out and becoming hard.

Bulk forming laxatives are often prescribed by doctors for those with long-term constipation problems.

Examples of bulk forming laxatives are Metamucil (Psyllium husk), Flaxseed (Linum usitatissimum), Fenugreek (Trigonella foenum-graecum), Barley (Hordeum vulgare) and Citrucel (Methylcellulose).

Bulk forming laxatives take anywhere from 12 to 72 hours to relieve constipation.  Bulk forming laxatives can cause bloating and gas, especially if the probiotic balance of the gut has been compromised.

Some individuals are allergic to Psyllium, and may react violently to it.

Lubricant laxatives

These may either be plain mineral oil or an emulsion - a combination of oil and water. When used to relieve constipation, the oil stays in the intestine and coats the stool, causing it to retain water.

Mineral oil causes the fat soluble vitamins to be pulled out of the intestinal wall. It also tends to block the absorption of vitamins and other nutrients.

Therefore lubricant laxatives should only be used for a limited amount of time.

Stimulant laxatives

Stimulant laxatives are an irritant that causes the colon muscles to contract, pushing stool through the colon more quickly.

Examples of stimulant laxatives are Cascara (Castor oil) and Senna (Senokot). These laxatives are effective in treating constipation, but can cause severe diarrhea, dehydration and electrolyte imbalances.

The colon can also become dependent on them to stimulate contractions. This can make the constipation problem worse when they are withdrawn.


Enemas are also a form of laxative. They stimulate the colon to contract and force out stool.

Different types of enemas are available:

  • Saline enemas, which draw water into the colon

  • Phosphate enemas, which stimulate colon muscles to contract

  • Mineral oil enemas have oil that softens the stool

  • Emollient enemas contain ingredients that soften the stool

All of these laxatives are used when stool is hard, impacted and difficult to eliminate. As with all laxatives, follow the instructions carefully for maximum effect. 

Conclusion, relieving constipation

Different laxatives work in different ways. It is important to be aware of how each functions, and of possible side effects.

Some products, including bulk forming laxatives and a magnesium supplement, may be used long-term for relieving constipation.

(Return from Relieving Constipation to What to Take for Constipation)

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