

Colac Mg | Taisho Pharmaceutical
Constipation medicine containing non-stimulant magnesium oxide, less likely to cause stomach pain.
For these people and situations
Product overview
"Colac Mg" is a constipation medicine from Taisho Pharmaceutical's Colac brand "Gentle Series." It uses non-stimulant magnesium oxide (Mg) as the active ingredient, which attracts water by osmotic pressure in the intestines, expanding and softening stool to support natural-like bowel movements.
The formulation design includes unique features that allow the tablet to start dissolving immediately upon entering the mouth, reducing the chance of it getting stuck in the throat. The magnesium oxide particles are fine, minimizing gritty texture. The raw material is a highly refined product derived from Seto Inland Sea seawater, confirmed to have heavy metal content near the quantification limit.
Product features
Non-stimulant ingredient, less likely to cause stomach pain
Magnesium oxideInstead of directly stimulating the intestines, it uses osmotic pressure inside the intestinal tract to attract water and soften stool. This mechanism differs from stimulant ingredients like bisacodyl or sennosides, making it less likely to cause stomach pain.
Works on hard stool as well
Intestinal water-attracting actionAttracts water to the intestines to soften hardened stool, effective even for stool that tends to become hard due to lack of water or dietary fiber.
Easy-to-take formulation design
Special formulation technologyFormulated to dissolve immediately in the mouth. Tablets are less likely to get stuck in the throat, making them easy to take for women and Elderly. The fine particles of magnesium oxide also reduce the gritty feeling.
Uses high-quality raw materials
Derived from Seto Inland Sea waterThe raw material is a highly refined product derived from the seawater of the rich Seto Inland Sea. It has been confirmed that the heavy metal content is near the quantification limit, achieving tablets with high whiteness.
Active ingredient
| Ingredient name | Content (per 6 tablets) | Classification and action |
|---|---|---|
| Magnesium oxide | 1,980 mg | Non-stimulant laxative ingredient |
[Additives] Cellulose, croscarmellose sodium (cross CMC-Na), calcium stearate
Indications and Effects
Dosage and administration
Take the following amount with water or lukewarm water before bedtime (or on an empty stomach). However, start with the minimum dose for the first time and gradually increase or decrease the dose while monitoring bowel movement condition.
| Age | Dose per time | Number of doses per day |
|---|---|---|
| 15 years and older | 3–6 tablets | Once |
| 11–14 years old | 2–4 tablets | Once |
| 7–10 years old | 2–3 tablets | Once |
| 5–6 years old | 1–2 tablets | Once |
| Under 5 years old | Do not take | |
・How to remove tablets: Press the raised part of the PTP sheet firmly with your fingertip to break the aluminum foil on the back, then take out and take the tablet. (Be careful not to swallow it accidentally as is.)
・Colac Mg attracts water to the intestines, so it is recommended to take it with a glass of water or lukewarm water (180–200cc or more).
Comparison with the Colac series
| Comparison items | [Colac Mg] | Colac | Colac II | Colac suppository type |
|---|---|---|---|---|
| Drug classification | Class 3 OTC Drug | Class 2 OTC Drug | Class 2 OTC Drug | Class 3 OTC Drug |
| Dosage form | Tablet (oral) | Tablet (oral) | Tablet (oral) | Suppository (rectal insertion) |
| Main active ingredients | Magnesium oxide | Bisacodyl | Bisacodyl + DSS (dioctyl sodium sulfosuccinate) | Sodium bicarbonate and anhydrous sodium dihydrogen phosphate (carbon dioxide generation) |
| Mechanism of action | Attracts water into the intestines to soften stool (non-stimulant) | Directly stimulates the large intestine to activate intestinal movement (stimulant) | Two-component action: stimulation of the large intestine (bisacodyl) + water penetration into stool (DSS) | Generates carbon dioxide gas in the rectum to promote intestinal movement (local action) |
| Stimulation to the stomach | Less likely to cause stomach pain | May cause stomach pain | May cause stomach pain | Less likely to cause abdominal pain (local rectal action) |
| Dependence Resistance | Less likely to cause dependence | The body may become accustomed with long-term use | The body may become accustomed with long-term use | Avoid long-term continuous use |
| Onset of Effect | Take before bedtime for effect the next morning (varies by individual) | 6–11 hours after taking (varies by individual) | 6–11 hours after taking (varies by individual) | About 10–30 minutes after taking (fast-acting) |
| Indications and Effects | Relief of constipation and associated symptoms (head heaviness, skin problems, abdominal bloating, etc.) | Chronic and habitual constipation | Relief of constipation and associated symptoms (head heaviness, skin problems, abdominal bloating, etc.) | Constipation |
| Target Age | 5 years and older (dosage varies by age) | 15 years and older (not for under 15) | 15 years and older (not for under 15) | 12 years and older |
| For these people | For those seeking a constipation medicine that is less likely to cause abdominal pain, those concerned about hard stool, or first-time users of laxatives | For those with chronic or habitual constipation who want strong effects | For those who want to soften stool by penetrating water and want strong effects with two ingredients | For those seeking fast-acting effects, those who dislike oral medicine, or those looking for an alternative to enemas |
*This comparison is based on official information from each product. Effects and efficacy vary by individual. Please check the package inserts of each product before use.
❓ Frequently Asked Questions
QHow much water should I drink with Colac Mg?
ASince it draws water into the intestines, it is recommended to take it with 2 to 3 glasses of water or lukewarm water. At least one glass (180–200cc) is necessary.
QCan I take it together with other constipation medicines?
ADo not take other laxatives while using this product.
QHow many days should I take it before stopping if there is no effect?
AIf symptoms do not improve after about one week of use, stop taking it and consult a doctor, pharmacist, or registered seller.
QHow is it different from stimulant laxatives like bisacodyl?
AThe active ingredient in Colac Mg, "magnesium oxide," is a non-stimulant ingredient with a different mechanism of action from bisacodyl or sennosides. Instead of directly stimulating the intestines, it works by drawing water into the intestines to soften stool, making it less likely to cause dependence.
🌱 Brand Story
Colac is a leading constipation medicine brand in Japan developed by Taisho Pharmaceutical. "Colac Mg" was newly launched in April 2019 as part of the Colac brand's "Gentle Series." It was developed to meet the needs of first-time users of laxatives and those seeking a natural bowel movement, using a different approach from traditional stimulant ingredients (such as bisacodyl). Manufacturing and sales are handled by Taisho Pharmaceutical Co., Ltd. (Toshima-ku, Tokyo), and the marketing authorization holder is Magmitt Pharmaceutical Co., Ltd. (Kagawa Prefecture).
- Do not: take other laxatives while using this product.
- Consult a doctor, pharmacist, or registered seller before taking: those receiving medical treatment / pregnant or possibly pregnant women / Elderly / those with severe abdominal pain, nausea, or vomiting / those diagnosed with kidney disease
- If any of the following symptoms appear after taking this product, stop taking it immediately and consult a doctor, pharmacist, or registered seller: severe abdominal pain, nausea, vomiting / strong drowsiness, loss of consciousness / dizziness, slow pulse / difficulty breathing / muscle weakness, dry mouth
- If diarrhea symptoms persist or worsen, stop taking it and consult a doctor, pharmacist, or registered seller.
- If symptoms do not improve after taking for one week, stop taking it and consult a doctor, pharmacist, or registered seller.
- Store in a cool, dry place away from direct sunlight.
- Keep out of reach of children.
- Do not transfer to other containers (risk of misuse and quality changes).
- Do not take the product after the expiration date. Take it as soon as possible after opening.
















































































