This text is based on the latest medical evidence and my personal experience in selecting and recommending over-the-counter medications, without favoring any particular pharmaceutical company or product. If new medical evidence is published, the recommended medications will be promptly updated accordingly.
Many people are currently troubled by constipation.
There are various constipation medications available in Japanese pharmacies.
However, choosing the right medication for your body type is not an easy task.
Here, I will introduce five recommended laxatives and their effective usage methods.
Osmotic Laxatives
①Magnesium Oxide E Laxative（Kenei）
For those trying a constipation medication for the first time, it is recommended to use this medication.
This medication is a non-stimulant laxative (osmotic laxative) and is also commonly prescribed by hospitals in Japan.
The active ingredients directly reach the large intestine, drawing water into the large intestine, which causes the stool to expand and promotes bowel movements.
It has very few side effects and can be taken by children, pregnant women, and breastfeeding mothers.
Suitable for use from the age of 5.
Precautions
Elderly people and those with impaired renal function should be aware of hypermagnesemia (nausea, vomiting, muscle weakness, drowsiness, hypotension, etc.).
If this medicine does not work effectively, you can switch to a stimulant laxative introduced below. However, the best method is to use this medicine together with a stimulant laxative. In that case, take this medicine daily, and on the nights when you do not have a bowel movement, take the stimulant laxative. Do not take the stimulant laxative on the days you have a bowel movement. By doing this, you will usually find that the number of days you need to take the stimulant laxative will gradually decrease.
| Age | Single Dose | Frequency per Day |
|---|---|---|
| 15 years old or over | 3~6 tablets | One time |
| the age of 11~14 | 2~4 tablets | One time |
| the age of 7~10 | 2~3 tablets | One time |
| the age of 5~6 | 1~2 tablets | One time |
| Under the age of 4 | Not to be taken | |
Magnesium Oxide E Laxative（Kenei）
Stimulant Laxative
②ColacⅡ（Taisho）
Colace is the most well-known constipation medication in Japan.
This medication is a stimulant laxative, and its active ingredient, bisacodyl, directly stimulates the large intestine to promote bowel movements and relieve constipation.
It is commonly believed that long-term use of stimulant laxatives can lead to drug resistance, but this is not actually the case.
As long as it is not taken in large amounts, it is safe for pregnant and breastfeeding women to use.
Using it in combination with a non-stimulant laxative is also a good approach.
It can be used by individuals aged 11 and older.
Precautions
It should not be taken with milk or antacids. Otherwise, the coating of the medication will dissolve, and its active ingredients will be released in the stomach before reaching the large intestine.
| Age | Single Dose | Frequency per Day |
|---|---|---|
| 15 years old or over | 1~3 tablets | One time |
| the age of 11~14 | 1~2 tablets | One time |
| Under the age of 10 | Not to be taken | |
③Colac First（Taisho）
This medicine is one of the most famous laxatives in Japan, part of the Corac series.
Each tablet contains 2.5 mg of bisacodyl, which is half the amount found in Corac II, so you can start with a smaller dose and gradually adjust to the optimal amount for yourself.
It is recommended for people who have relieved their constipation with Corac II but experienced severe abdominal pain or diarrhea.
Precautions
It should not be taken with milk or antacids. Otherwise, the coating of the medication will dissolve, and its active ingredients will be released in the stomach before reaching the large intestine.
| Age | Single Dose | Frequency per Day |
|---|---|---|
| 15 years old or over | 1~4 tablets | One time |
| the age of 11~14 | 1~3 tablets | One time |
| Under the age of 10 | Not to be taken | |
④Daichi’s Chinese Herbal Laxative（Alinamin）
This medicine is suitable for people who have not found the previous three medicines effective, or those who suffer from long-term constipation and want an immediate solution. The herb rhubarb strongly stimulates the large intestine, promoting bowel movements and relieving constipation.
While it is commonly believed that long-term use of stimulant laxatives causes drug resistance, this is not actually the case.
This medicine may cause side effects such as abdominal discomfort and pain, and it is not suitable for people who are prone to abdominal pain.
It takes effect 8 to 10 hours after consumption.
Using it together with non-stimulant laxatives is also a good method.
It can be used by children from the age of 5.
Precautions
Rhubarb can cause uterine contractions and induce miscarriage, therefore it should not be taken by pregnant women.
| Age | No bowel movement for 2-3 days | No bowel movement for more than 4 days | Frequency per Day |
|---|---|---|---|
| Adult (15 years old or over) | 1~3 tablets | 2~4 tablets | One time before bed |
| the age of 5~14 | 1/2~1 tablet | 1~2 tablets | One time before bed |
| Under the age of 4 | Not to be taken | ||
Daichi’s Chinese Herbal Laxative（Alinamin）
Probiotics
⑤Miyarisan（Miyarisan Pharmaceutical）
Professor Hirata, my mentor at the Faculty of Pharmacy, highly recommends this medicine. and I take it every day as well.
Unlike the three medicines mentioned above, this one works by adjusting the gut microbiome to improve constipation.
Lactobacillus Miyairi reaches the large intestine alive, increases beneficial bacteria, and suppresses harmful bacteria, thereby regulating the gut microbiome.
It is effective for both constipation and diarrhea.
It has a slightly sweet taste and can also be chewed.
It is safe for anyone over the age of 5.
According to recent research, taking it daily is expected to have anti-cancer effects.
| Age | Single Dose | Frequency per Day |
|---|---|---|
| 15 years old or over | 3 tablets | Three times |
| the age of 11~14 | 2 tablets | Three times |
| the age of 5~10 | 1 tablet | Three times |
| Under the age of 4 | Not to be taken | |
Miyarisan（Miyarisan Pharmaceutical）
