Cool One in Japan: Expectorant Capsules, GX Plus Tablets or GX Liquid?

I'm Irene, a Taiwan-born pharmacist licensed in Japan and currently working in a Japanese drugstore. Cool One is a good example of why I check the complete product name before the packaging color: the green expectorant capsules and the GX cough medicines do different jobs, and their age limits are different too.

For phlegm and a phlegmy cough, start by asking about Cool One Expectorant Soft Capsules. GX Plus tablets and GX liquid also contain a cough suppressant and an antihistamine, with additional safety restrictions. None should be added to another cold or cough medicine on your own. This comparison helps you identify the options; cough type alone cannot establish its cause or tell you that self-treatment is appropriate.

Japanese manufacturer pages and the actual linked package leaflets checked on October 14, 2026 (Japan time). Follow the leaflet in your own pack. The product here is GX Plus: Kyorin renewed the older GX tablets in July 2022, adding tranexamic acid and an indication for cough/phlegm accompanied by throat pain.

Three names to recognize at the drugstore

The useful dividing line is the formula

• Expectorant Soft Capsules: two phlegm-clearing ingredients, L-carbocisteine and bromhexine. Labeled for phlegm and cough with phlegm. They do not contain the GX products' dihydrocodeine or antihistamine.
• GX Plus tablets: labeled for cough, phlegm, and cough/phlegm accompanied by throat pain. They contain dihydrocodeine and chlorpheniramine, plus tranexamic acid. This is a combination cough medicine, not a phlegm-only capsule.
• GX liquid: labeled for cough and phlegm. Useful to discuss if tablets are difficult to swallow, but it is not GX Plus dissolved in a bottle: it has no tranexamic acid and different amounts of several active ingredients.

Active ingredients on an adult daily basis

All amounts below are in milligrams (mg) per labeled adult day, age 15 and over: 6 expectorant capsules, 6 GX Plus tablets or 30 mL GX liquid. A dash means the ingredient is not included as an active ingredient. These are not per-dose amounts.

The same L-carbocisteine total is a reason to check for duplication, not to take these products together. Nor should you double the liquid to match a tablet ingredient amount. More ingredients or a higher number does not automatically make a product a better match for your cough.

Doses and ages: do not carry one product's rules across

This table shows the labeled amount per dose, separately from daily frequency. “Age 8–14” means at least 8 but under 15; “12–14” means at least 12 but under 15. Children must take permitted products under a parent or guardian's supervision.

A liquid medicine is not automatically a children's medicine. The GX liquid's 120 mL pack size must not be confused with its 10 mL adult dose. Remove tablets or capsules from the blister before taking them, keep medicines in their original containers, and keep them out of children's reach. Wipe the liquid bottle mouth, close it firmly and wash the cup after use.

Driving, breastfeeding and other medicines

Consult a doctor, pharmacist or registered medicine seller before choosing any of these if you are receiving treatment, are pregnant or may be pregnant, are older, have had medicine allergies or have a high fever. The expectorant leaflet also lists heart or liver disease. For either GX product, professional checking is especially important with difficulty urinating, heart disease, high blood pressure, diabetes, glaucoma, liver disease, thyroid disease, impaired breathing, obstructive sleep apnea or obesity. GX Plus also requires consultation for a blood clot or risk of thrombosis. Bring the complete medicine list, including throat remedies and prescriptions.

The stopping point is different

• Expectorant Soft Capsules: stop and consult if symptoms have not improved after 3–4 days.
• GX Plus or GX liquid: stop and consult if symptoms have not improved after 5–6 doses. This means doses, not days.
• Stop promptly for a rash, vomiting, abdominal symptoms, dizziness or other suspected adverse effects. If side effects such as constipation, dry mouth or drowsiness persist or worsen with a GX product, stop and seek advice; the capsule leaflet separately lists diarrhea and dry mouth.
• Breathing difficulty, a severe skin reaction, or signs of a serious allergic reaction require immediate medical attention. The GX leaflets include respiratory depression among rare serious reactions. Do not keep suppressing a worsening or recurrent cough without assessment.