- Research suggests that cassia bark might help control blood sugar in people with type 2 diabetes, but the evidence isn’t strong enough yet.
- It seems to have antifungal properties, but most of this is based on lab studies, and it’s still unclear how well it works in humans.
- Eating too much could harm the liver because it contains coumarin, so it’s best to be careful.
- You can add a moderate amount to your daily diet, but if you have liver issues, it’s a good idea to check with your doctor first.
- In Western countries, it’s often used as a spice in baking and desserts.
Cassia bark, known as Rougui (肉桂) in Traditional Chinese Medicine (TCM), is a potent herb celebrated for its warming properties and versatility. Often mistaken for its milder cousin, Ceylon cinnamon, cassia bark stands out with its bold flavor and rich history in both healing and cooking.
Whether you’re curious about its role in TCM or wondering how it might spice up your life, this article dives into what cassia bark is, its potential benefits, and how to use it safely—all backed by tradition and science.
What Is Cassia Bark (Rougui)?
Cassia bark comes from the Cinnamomum cassia tree, an evergreen native to southern China, particularly regions like Guangxi, Guangdong, and Yunnan. In TCM, it’s called Rougui and valued as a warming herb. Known scientifically as Cinnamomi Cortex or CORTEX CINNAMOMI, it’s the dried inner bark of the tree, distinct from Ceylon cinnamon (Cinnamomum verum), often dubbed “true cinnamon.”
- Appearance: Picture thick, rough strips—grayish-brown outside, reddish-brown inside—rolled into quills or ground into powder. It’s sturdier than the delicate layers of Ceylon cinnamon.
- Flavor and Aroma: Its scent is warm and intense, like a spiced holiday dessert, with a sweet-spicy kick that lingers.
In TCM, cassia bark is described as “hot,” with a sweet and pungent taste. It’s said to flow into the kidney, spleen, heart, and liver meridians, warming the body from the inside out. Ancient texts like The Divine Farmer’s Materia Medica (Shennong Bencao Jing) praise it for easing coughs, improving circulation, and boosting energy1.
Health Benefits of Cassia Bark (Rougui)
Cassia bark has been a TCM staple for centuries, targeting “cold” conditions and poor circulation. Modern research is starting to catch up, offering glimpses into its potential. Here’s what tradition and science say about its benefits:
1. Warms the Body and Chases Away Cold
In TCM, cassia bark is a natural heater for the body, perfect for2:
- Cold hands and feet
- Stomach pain from eating cold foods
- Joint stiffness that worsens in chilly weather
It’s like wrapping yourself in a warm blanket on a winter day, coaxing blood to flow and easing that deep chill. Ancient texts, like Kaibao Bencao, note its ability to “warm muscles and unblock channels.”
2. May Help Manage Blood Sugar
Research hints that cassia bark could support blood sugar control, especially for type 2 diabetes. A 2021 meta-analysis found that 1-2 grams daily for 90 days lowered fasting blood sugar and HbA1c levels. While promising, this isn’t a green light to swap it for your meds—more studies are needed.
Friendly Reminder: Talk to your doctor before adding cassia bark to your diabetes plan.
3. Fights Fungi in the Lab
Cassia bark’s essential oil, rich in cinnamaldehyde, shows antifungal promise against Candida albicans, according to a 2023 study. While exciting, this is lab-based—human evidence is still brewing.
4. Boosts Antioxidants
Loaded with compounds like catechins, cassia bark helps fight oxidative stress3. It’s a small but welcome perk for overall wellness.
Summary: Cassia bark has been a TCM staple for centuries. It warms the body, may help manage blood sugar, shows antifungal effects in the lab, and boosts antioxidants. But more research is needed, especially for practical applications.
How to Use Cassia Bark (Rougui)
Cassia bark shines in both TCM and the kitchen. Here’s how it’s traditionally enjoyed:
In Traditional Chinese Medicine (TCM)
- Tea or Decoction: Boil 2-5 grams with herbs like ginger for a warming drink to ease cold-related aches or menstrual cramps.
- Powder: Take 1-2 grams mixed with water to boost circulation.
- Topical: Rub a paste or oil on sore spots for relief4.
Example: In formulas like You Gui Wan, cassia bark teams up with herbs to tackle fatigue and cold sensitivity5.
In the Kitchen
- Spice Blends: It’s a star in Chinese five-spice or garam masala.
- Cooking: Simmer a stick in soups, stews, or rice for depth. Guangxi’s cassia, with its high oil content, is a chef’s favorite.
- Drinks: Steep it in tea or hot chocolate for a cozy twist.
Tip: A little goes a long way—its bold flavor can steal the show if overdone.
Sample Recipe: Cassia Bark Porridge
For chilly days or weak digestion:
- Boil 50g rice into porridge.
- Add 3g cassia bark (decoct first, strain, then mix in) and a spoonful of brown sugar.
- Enjoy warm to soothe a cold stomach.
Safety Considerations for Cassia Bark
Cassia bark is powerful, but it’s not without risks. Here’s what to watch for:
1. Coumarin Concerns
Unlike Ceylon cinnamon, cassia bark has higher coumarin levels—a compound that can harm the liver in excess6. The European Food Safety Authority sets a safe limit at 0.1 mg per kg of body weight daily (about 7 mg for a 150-pound person, or roughly 1 teaspoon of cassia powder).
- Liver Caution: If you have liver issues, check with your doctor.
- Safer Swap: Ceylon cinnamon has negligible coumarin and is better for daily use.
2. Who Should Avoid It?
- Pregnancy: Its warming nature might stimulate the uterus—skip it if you’re expecting7.
- Bleeding Risks: It may thin blood, so avoid it if you’re on anticoagulants or prone to bleeding8.
- Heat Sensitivity: If you’re prone to dry mouth or hot flashes (TCM’s “yin deficiency”), use it sparingly9.
3. Side Effects
Rarely, it might irritate skin or upset your stomach. Stop if you feel off.
Summary: Cassia bark has risks. It has high coumarin, which can harm the liver. Pregnant women, those with bleeding risks or heat sensitivity should avoid it. Rarely, it may cause skin or stomach problems.
How to Use it Safely
- TCM Dose: 2-5 grams for teas (add late to avoid overcooking), 1-2 grams as powder10.
- Cooking: A pinch or small stick is plenty.
- Frequency: Keep it occasional—daily use risks coumarin buildup.
- Expert Advice: Consult a TCM practitioner or doctor, especially for medicinal use.
Pro Tip: Worried about coumarin? Save cassia for special dishes and lean on Ceylon cinnamon for everyday sprinkling.
Cassia Bark vs. Ceylon Cinnamon: A Quick Look
| Feature | Cassia Bark | Ceylon Cinnamon |
|---|---|---|
| Coumarin | High (3000-10000 mg/kg)11 | Low (negligible) |
| Flavor | Bold, spicy | Subtle, sweet |
| Uses | TCM, hearty dishes | Desserts, daily use |
| Safety | Moderation key | Safer for regular use |
Modern Research on Cassia Bark
Science is digging into cassia’s potential beyond TCM:
- Circulation: It may widen blood vessels and boost brain and heart blood flow12.
- Digestion: Studies suggest it eases stomach spasms and supports gut movement13.
- Blood Sugar: Early evidence points to glucose-lowering effects14.
These findings are exciting but preliminary—human studies are still catching up to centuries of traditional use.
The Bottom Line
Cassia bark (Rougui) is more than a spice—it’s a bridge between ancient TCM wisdom and modern curiosity. From warming your core to potentially steadying blood sugar, it’s a versatile herb when used with care. Its high coumarin content means moderation is key, especially compared to Ceylon cinnamon. Whether you’re simmering it in soup or sipping it in tea, cassia bark brings a touch of warmth and tradition to your table.
Have you tried cassia bark? I’d love to hear how it’s spiced up your life—or your health routine!
Trusted Source
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- https://m.baidu.com/bh/m/detail/ar_2528304672647014284(Chief Physician Yu Rong Department of Obstetrics and Gynecology, Xuanwu Hospital of Capital Medical University) ↩︎
- https://www.verywellhealth.com/can-cinnamon-lower-blood-pressure-4126313 ↩︎
- https://m.baidu.com/bh/m/detail/ar_1001750932998642375(Li Haitao, Attending Physician, Department of Traditional Chinese Medicine, The First Affiliated Hospital of Henan University of Traditional Chinese Medicine) ↩︎
- 徐立鹏,仝小林.肉桂现代临床用量研究[J].中国临床医生杂志, 2015(10):4.DOI:10.3969/j.issn.2095-8552.2015.10.032. ↩︎
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