Discover Japan’s Traditional Healing Bath – Seiyu-yu
April’s Onsen Box features something truly special – Seiyu-yu, a traditional Japanese herbal bath developed by Seishindan, a company with centuries of expertise in medicinal herbs. This bath blend is made exclusively from Wasei Aroma—Japanese-grown medicinal herbs that have been used since the Edo period for relaxation and wellness.
The Secret Behind Seiyu-yu
Seiyu-yu is a yakuto (medicinal bath) crafted from premium-grade medicinal plants, many of which are also used in traditional herbal medicine. Its unique formula includes:
- Angelica root (Tōki) – Known for promoting circulation and relieving cold sensitivity.
- Ginger (Shōkyō) – A warming ingredient that enhances blood flow.
- Star Anise (Daiuikyō) – A fragrant spice with relaxing properties.
- Dried Tangerine Peel (Chinpi) – Rich in essential oils that calm the mind.
- Cnidium Rhizome (Senkyū) – Often used in herbal remedies to improve circulation.
How It Works
Once the herbal blend is added to hot water and gently massaged, the bathwater transforms into a golden hue, releasing a rich, earthy aroma. This is the power of essential oils extracted from fresh herbs. Unlike traditional decoctions where many aromatic compounds are lost through boiling, a medicinal bath preserves and maximizes these natural essences, allowing you to inhale their benefits directly.
The Science of Aroma Healing
Ever noticed how certain scents instantly bring back memories or emotions? That’s because our sense of smell is directly linked to the limbic system in the brain, which controls emotions and memory. The essential oils in Seiyu-yu trigger a relaxation response, reducing stress and promoting deep tranquility. As your body absorbs the herbal extracts through the skin, circulation improves, easing muscle tension and fatigue.
The History of Seishindan
The origins of Seishindan trace back over two centuries to the Edo period.
- 1801 (Kyōwa 1st year) – The first-generation founder, Yohei Takagi, established a medicinal herb wholesaler in Moto-Osaka-cho, Nihonbashi, Edo (modern-day Tokyo).
- 1824 (Bunsei 7th year) – The company’s flagship product, Seifu-tō, a herbal remedy for women’s health, was featured in Edo Kaimono Dokuan’nai, a famous guidebook of Edo’s specialty stores. During this period, the company was known under the trade name “Sakaiya.”
With a rich legacy of herbal medicine expertise, Seishindan continues to bring the benefits of traditional Japanese healing to modern-day wellness practices.
Experience the Magic of Japanese Herbal Baths
With Seiyu-yu, you’re not just taking a bath—you’re indulging in a centuries-old wellness ritual. This spring, let the power of Japanese medicinal herbs transform your bath into a sanctuary of warmth, relaxation, and renewal.
Try Seiyu-yu with your April Onsen Box and experience Japan’s natural healing traditions at home!
Benefits & Effects
Seiyu-yu is known to help with:
- Cold sensitivity
- Lower back pain
- Shoulder stiffness
- Fatigue recovery
- Neuralgia
- Bruises & sprains
- Hemorrhoids
- Rheumatism
- Pre- and post-natal cold sensitivity
- Rough skin
- Heat rash
- Eczema
- Chilblains
- Cracked skin
- Acne
How to Use
Add two sachets (15g each) of Seiyu-yu to a standard household bathtub (approximately 200L of water). Gently squeeze and stir the sachets to release the herbal essence before entering the bath.
Recommended Usage
- Soak the sachets lightly in warm water (38–40°C).
- Relax and soak for 10–15 minutes.
- After bathing, rinse your body and rest for 20 minutes. For those with cold sensitivity, repeat the process several times.
- Be mindful of keeping warm after bathing to avoid chills.
- For the best sleep quality, enter bed as your body temperature starts to drop.
- For half-body baths or foot baths, use one sachet (15g) instead.
Note: Effects may vary by individual.
