Japan-market official product information and instructions checked: 1 November 2026. This buying guide does not replace the complete instructions in your box.
Picked a hair colour in a Japanese drugstore and planning to use it at the hotel tonight? With Japan’s Liese 泡カラー foam hair colour, application time is not preparation time. People who meet the conditions for use must complete the instructed 48-hour skin allergy test before every application—even if previous colouring caused no problems.
I’m Irene, a Taiwan-born, Japan-licensed pharmacist working in a Japanese drugstore. Here, I would check whether you should start at all—and whether your schedule allows the required preparation—before helping you choose a shade.
Identify the product: foam colour is not colour shampoo
This guide uses Japan’s リーゼ 泡カラー ディープバイオレット (Deep Violet) as the identification example. The dye is a Japanese quasi-drug; the official product page lists LAW24 first solution and second solution d. The supplied hair treatment is a separate product. This is a dye for dark hair, not a dedicated grey-coverage product and not something to use as shampoo.
Do not transfer instructions from another Liese colour shampoo, a bleach or an overseas Liese product. The brand currently announces a packaging update, so store boxes may look different. Check the complete name, shade and instructions supplied with your box rather than relying on its colour.
What the supplied items are for
Two checks before you buy
1. A patch test is not the first step for everyone
The current instructions say not to use the product if you have reacted to any hair dye; experienced hives, nausea, dizziness or other illness during or immediately after colouring; had an abnormal patch-test response; have an unusually sensitive scalp or skin, including during illness, recovery, menstruation or pregnancy; have swelling, wounds or skin disease on your head, face or neck; have kidney or blood disorders; or have persistent signs of ill health such as slight fever, fatigue, palpitations, shortness of breath, purple spots, easy bleeding or bleeding that is difficult to stop. Do not use on young children.
2. Can you follow the full instructions for 48 hours?
Even without those concerns, a skin allergy test is required 48 hours before every application. Prepare and observe it exactly as instructed in your box. Previous trouble-free use does not rule out a new reaction. The instructions call for observations about 30 minutes after application and after 48 hours. A normal-looking result at 30 minutes is not permission to colour early.
For example, buying it tonight to use tonight does not leave the required time. Shortening the test to 24 hours or colouring a small strand is not a substitute. Move the colouring date; if your itinerary cannot accommodate the complete requirements, do not buy it for that immediate-use plan. This is a scheduling example, not a personal safety clearance.
Do not wait out a reaction
If a rash, redness, itching, blisters, irritation or another abnormality develops during testing, stop the test, wash off the test mixture and do not colour your hair. This also applies before the 48 hours are up. Ask a doctor or Kao; do not switch brands or repeat the test the next day to get a “pass”.
No abnormality observed under the instructions is not a guarantee against allergy. All other restrictions and precautions still apply. During colouring, skin abnormalities, hives, nausea or dizziness mean rinsing off the dye immediately and obtaining medical care. Seek medical care for abnormalities appearing after colouring too. Hair dye can cause severe allergic reactions.
Take these three points to the counter
- Complete name and shade: show the actual box and instructions, not just the brand name.
- Past reactions and current conditions: mention even a previous episode of itching. Ask first if you are unsure.
- Planned colouring time: can you complete the required test before every use? If you cannot understand or follow the instructions, postpone rather than skip a step.
This article does not teach mixing, application or processing times. Read the full instructions before use. In particular, do not use on eyebrows, eyelashes or anywhere other than scalp hair, do not use while bathing, and do not store mixed dye. Convenience on a trip should not depend on shortening the checks.
