Constipation Medicine in Japan: OTC Laxatives, Ingredients, and Safety Checks

General information only: This article is for travelers and residents who want to understand common over-the-counter constipation medicine options in Japan. It does not diagnose your condition or replace medical, pharmacist, or emergency advice.

Constipation can happen during travel because of dehydration, less walking than usual, long flights, changes in meals, stress, or a different bathroom routine. In Japan, drugstores sell several types of OTC constipation products, including osmotic laxatives, stimulant laxatives, herbal laxatives, suppositories, and enemas.

However, constipation medicine is not always the right answer. If constipation comes with severe abdominal pain, vomiting, a swollen abdomen, blood in the stool, fever, dehydration, or inability to pass gas, medical care may be more important than OTC medicine.

This guide explains common ingredient names you may see on Japanese OTC constipation medicine labels, what to check before buying, and when to ask pharmacy staff or seek medical care.

Quick Answer: What to Check First

Before buying or taking OTC constipation medicine in Japan, check:

• the active ingredient
• the product’s “do not use” and “ask before use” warnings
• whether the person taking it is a child, elderly person, pregnant person, or someone with a chronic condition
• whether there is abdominal pain, vomiting, bloating, blood in the stool, fever, dehydration, or inability to pass gas
• whether the person has kidney disease, heart disease, digestive disease, or takes other medicines
• whether the person has already used another laxative or constipation product

If you are unsure, show the product to a pharmacist or registered salesperson before buying it.

Do not use multiple OTC constipation medicines together on your own. Different laxatives, stomach medicines, magnesium products, herbal medicines, and other OTC medicines may contain overlapping ingredients or warnings.

Constipation Medicine in Japan: Quick Checklist

Use this checklist before choosing a product:

• How many days has it been since the last bowel movement?
• Is there severe or worsening abdominal pain?
• Is the abdomen very bloated or hard?
• Is there nausea, vomiting, fever, blood in the stool, or black stool?
• Can the person pass gas?
• Is the person able to drink fluids and urinate normally?
• Is the person a child, elderly person, pregnant, breastfeeding, or medically fragile?
• Is there kidney disease, heart disease, liver disease, intestinal disease, stomach or duodenal ulcer history, or regular medication use?
• Does the package say not to use the product in your situation?
• Is pharmacist or registered salesperson confirmation required?

If any answer worries you, do not rely on OTC medicine alone.

If you are not sure how to find medical care in Japan, see our guide: 旅行者が日本で医療機関を受診する方法.

Common OTC Constipation-Related Ingredients You May See

The ingredient names below are label clues, not recommendations. Product warnings differ by brand, dose, age limit, and combination ingredients. Always read the package and ask pharmacy staff if you are unsure.

Ingredient name you may see	What it is usually used for	Important checks
Magnesium oxide / magnesium hydroxide / magnesium-containing laxatives	Osmotic or saline-type laxatives that help draw water into the stool	Ask pharmacy staff first if you have kidney disease, are elderly, have heart disease, or take other medicines. Magnesium products can be risky when magnesium builds up in the body, especially with reduced kidney function.
Sennosides / senna / rhubarb-related ingredients	Stimulant-type laxatives that stimulate bowel movement	Do not use repeatedly or long term on your own. Ask first if you have abdominal pain, nausea, vomiting, suspected bowel blockage, pregnancy, dehydration, or if the medicine is for a child.
Bisacodyl	Stimulant laxative, often used in tablets or suppositories	Check the package carefully. Do not use on your own if you have severe abdominal pain, nausea, vomiting, or suspected bowel blockage. Some products have timing cautions with milk or antacids.
Sodium picosulfate hydrate	Stimulant-type laxative	Check age limits and dose. Avoid repeated self-use. Ask pharmacy staff first if pregnant, elderly, medically fragile, or if abdominal pain or vomiting is present.
Docusate sodium / DSS	Stool-softening ingredient, sometimes combined with stimulant laxatives	Check whether the product contains other laxative ingredients. Do not assume it is mild just because it includes a stool softener.
Glycerin enema / glycerin suppository	Rectal product used to stimulate bowel movement	Ask first if there is strong abdominal pain, nausea, vomiting, rectal bleeding, severe hemorrhoid symptoms, or possible bowel blockage. Do not use frequently without professional advice.
Herbal or Kampo laxatives, such as rhubarb-containing formulas	Herbal constipation products; some act like stimulant laxatives	“Herbal” does not always mean gentle. Check whether the product contains rhubarb, senna-like ingredients, or glycyrrhiza-related ingredients. Ask first if you have high blood pressure, heart disease, kidney disease, low potassium concerns, pregnancy, or regular medication use.

Magnesium-Based Constipation Medicine

Magnesium oxide and related magnesium products are commonly used for constipation. They usually work by drawing water into the stool and making it easier to pass.

Important checks:

• Ask pharmacy staff before use if you have kidney disease.
• Be careful if you are elderly, dehydrated, medically fragile, or taking several medicines.
• Magnesium products can interact with the timing or absorption of some medicines.
• Do not use them on your own if constipation comes with severe abdominal pain, vomiting, marked bloating, or inability to pass gas.

Magnesium constipation products may look simple, but they are not automatically safe for everyone.

Stimulant Laxatives: Senna, Sennosides, Bisacodyl, and Sodium Picosulfate

Stimulant laxatives help move the bowel by stimulating intestinal movement. They may work faster than some other options, but they are not a good product to use repeatedly without checking the cause of constipation.

Important checks:

• Do not use stimulant laxatives long term on your own.
• Do not keep increasing the dose because the first dose did not work quickly.
• Ask pharmacy staff first if you have abdominal pain, nausea, vomiting, dehydration, or a very bloated abdomen.
• Ask first if pregnant, elderly, medically fragile, or if the medicine is for a child.
• If constipation keeps coming back, consider medical care rather than repeated OTC laxative use.

Stimulant laxatives can cause cramping, diarrhea, or dehydration if the product is not appropriate or is used too much.

Glycerin Enemas and Suppositories

Some Japanese drugstores sell glycerin enemas or suppositories. These are different from oral tablets or powders because they act from the rectum.

They may be useful in some situations, but they are not the right choice for every traveler.

Ask pharmacy staff first if:

• there is severe abdominal pain
• there is nausea or vomiting
• the abdomen is very swollen
• you cannot pass gas
• there is rectal bleeding
• there are severe hemorrhoid symptoms
• the product is for a child, elderly person, pregnant person, or medically fragile person

Do not use enemas repeatedly just to force bowel movements during a trip. If constipation is persistent or unusual, medical care may be safer.

Herbal and Kampo Constipation Products

Some constipation products in Japan contain herbal or Kampo ingredients. These may include rhubarb-related ingredients or formulas used for constipation.

Do not assume that herbal products are always mild. Some herbal laxatives act like stimulant laxatives. Some products may also contain glycyrrhiza-related ingredients, which can matter for people with high blood pressure, heart disease, kidney disease, low potassium concerns, or people taking certain medicines.

If you are already taking Kampo, herbal supplements, blood pressure medicine, heart medicine, diuretics, or other regular medicines, ask pharmacy staff before buying a herbal constipation product.

Do Not Use Constipation Medicine to Cover Severe Symptoms

Constipation can sometimes be a sign of something more serious. OTC constipation medicine may not be appropriate if the bowel may be blocked, inflamed, bleeding, or affected by another illness.

Seek medical care promptly if you have:

• severe or worsening abdominal pain
• 繰り返す嘔吐
• a swollen or hard abdomen
• inability to pass gas
• blood in the stool or black stool
• fever
• dehydration
• sudden constipation that is very unusual for you
• unexplained weight loss
• constipation that does not improve or keeps recurring

If the situation feels severe or urgent, ask nearby staff for help or call 119 in Japan.

If Constipation Happens During Travel

Mild travel-related constipation can sometimes improve with simple steps, depending on your condition:

• drink fluids regularly
• avoid dehydration, especially during hot weather
• walk or move when possible
• eat regular meals if you can
• avoid delaying bathroom use for too long
• review whether a medicine you already take may cause constipation

These steps are not a substitute for medical care. If symptoms are severe, unusual, or not improving, do not rely on self-care alone.

Useful Phrases to Show at a Japanese Pharmacy

You can show these phrases to pharmacy staff. Choose the phrases that match your situation.

What you mean	Japanese to show
I am constipated.	便秘です。
I have not had a bowel movement for ___ days.	___日間、便が出ていません。
I have abdominal pain.	腹痛があります。
My abdomen is bloated.	お腹が張っています。
I feel nauseous.	吐き気があります。
I am vomiting.	嘔吐があります。
I cannot pass gas.	ガスも出ません。
There is blood in my stool.	便に血が混じっています。
I have kidney disease.	腎臓病があります。
I have heart disease.	心臓病があります。
I am pregnant or may be pregnant.	妊娠中、または妊娠している可能性があります。
I take other medicines.	他に服用している薬があります。
I want to know if OTC medicine is appropriate.	市販薬で対応してよいか確認したいです。
Please check whether this constipation medicine is safe for me.	この便秘薬を使ってよいか確認してください。

Related Guides

You may also want to read:

• Stomach and Digestive Problems in Japan: OTC Medicine Ingredients and Safety Checks
• Drugstore Basics in Japan: How to Buy OTC Medicine Safely
• Show This at a Japanese Pharmacy: OTC Medicine Questions in English and Japanese
• 旅行者が日本で医療機関を受診する方法

References

• Pharmaceuticals and Medical Devices Agency (PMDA). OTC medicine package insert search.
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Constipation treatment information.
• Japan National Tourism Organization (JNTO). Guide for when you are feeling ill in Japan.