Is Corydalis Rhizome Poisonous? A Detailed Guide to Consumption Methods, Planting, and Harvesting Times

Corydalis Rhizome, also known as Yuanhu Rhizome, Yuanhu, etc., is a common traditional Chinese medicine famous for its tubers. It is generally sown in early September. So is Corydalis Rhizome poisonous? How do you consume it? When is Corydalis Rhizome planted? When is it harvested? How do you grow it?

Is it poisonous?

Taking Corydalis Rhizome with correct compatibility and dosage will not cause poisoning. However, Corydalis Rhizome contains tetrahydropalmatine, which may cause liver poisoning. The Health Sciences Authority of Singapore has set the daily intake limit of tetrahydropalmatine at 19 milligrams. Therefore, do not take Corydalis Rhizome herbs on your own.

Consumption Methods:

1. Soaking in Liquor

This traditional Chinese medicine can be made into a health liquor for people to drink. When using it to make health liquor, prepare an appropriate amount of salted Corydalis Rhizome and yellow rice wine. Grind the prepared Corydalis Rhizome into a fine powder, heat the yellow rice wine in a pot, then after removing it add 5 grams of the ground Corydalis Rhizome powder, mix well and drink directly, twice a day. It can regulate qi and invigorate blood circulation and also relieve pain.

2. Boiling Eggs

Corydalis Rhizome can also be boiled with eggs together with Chinese motherwort. Usually take 10 grams of Corydalis Rhizome, 30 grams each of Chinese motherwort and 15 red dates, and 5 to 6 eggs. Wash them all with clean water, put them in a pot with clean water and bring to a boil. After the eggs are cooked, take them out and remove the shells, put them back in the pot, and continue boiling for 5 to 10 minutes. After cooking, take out and eat the eggs and drink the soup. It can effectively prevent irregular menstruation and menstrual abdominal pain in women.

Harvest Time:

Harvest after the above-ground stems and leaves wither. When digging, first plow shallowly, turning the soil while harvesting. After harvesting, deep plow once more, pick up all tubers cleanly, transport them indoors, spread them out and air-dry. During processing, wash off the soil, grade by size and put into baskets, place in running water, rub the outer skin clean by hand, wash clean and drain. Then, put the tubers into boiling water and boil until the cross-section of the tubers is yellow with no white core, then remove and spread on bamboo mats to sun-dry. After 4 to 5 days of sun-drying, bring indoors to “sweat”, allowing internal moisture to seep out, then sun-dry again until completely dry, and it becomes the commercial product. Quality is best when the tubers are large, plump, hard in texture, and yellow in cross-section.

Planting Techniques:

1. Site Selection and Land Preparation

It is best to choose a sunny, wind-sheltered, loose-textured, humus-rich sandy loam. After selecting the land, deep plow the soil 30 cm, and in conjunction with land preparation, apply 2000 kg of decomposed barnyard manure and 200 kg of cake fertilizer per mu (667 sq m, same below), turning them into the soil as base fertilizer. After leveling and raking fine, make raised beds 1.3 m wide, with a bed ditch width of 40 cm, and open drainage ditches around the perimeter.

2. Planting

When harvesting Corydalis Rhizome, select medium-sized, uniform, flat-spherical tubers with a transverse diameter of about 1.5 cm, pale yellow color, free of pests, diseases and scars, as seed tubers, and plant them at the appropriate time in late September. When planting, on the prepared bed surface, open furrows at a row spacing of 20 cm, a sowing width of 10 cm, and a furrow depth of 8 to 10 cm. Place the seed tubers with buds facing upward at a plant spacing of 7 cm, with two rows staggered in the furrow. After planting, cover with fertile fine soil until the furrow is full.

3. Field Management

Corydalis Rhizome is a shallow-rooted crop, so intertillage cultivation is not advisable. When seedlings are 3 cm tall, apply 1500 kg of decomposed human and animal manure water per mu, and weed promptly. In late November, spread a layer of cake fertilizer on the bed surface at 50 kg per mu, then cover with a layer of decomposed barnyard manure at 2000 kg per mu, and cover with fine soil after fertilizing. During rain, promptly dredge ditches for drainage; during drought, irrigate. Except for seed plots, when flower buds appear on Corydalis Rhizome, remove them promptly so that nutrients are concentrated on root growth, increasing yield.

4. Pest and Disease Control

(1) Downy Mildew

Leaves are affected first. In the early stage, brown irregular lesions appear. When humidity is high, a white mold layer appears on the underside of leaves. Affected stems and leaves quickly turn brown and die, and the plant dies. Control methods: First, implement rice-upland crop rotation; second, plant at reasonable density to improve ventilation and light conditions; third, in the early stage of disease, spray with 25% Ridomil wettable powder at 600 to 800 times dilution, once every 10 days, for 3 consecutive sprays.

(2) Sclerotinia Rot

First, yellow-brown or dark brown spindle-shaped lesions appear on the stem base near the soil surface. When humidity is high, the stem base becomes soft and rots, and the plant lodges. When leaves are affected, water-soaked elliptical lesions initially appear, then turn blue-brown. When the disease is severe, plants die in patches, and the soil surface is covered with white cotton-like mycelium and black mouse-dropping-shaped sclerotia of varying sizes. Control methods: First, implement rice-upland crop rotation; second, after rain, promptly drain field water to reduce field humidity; third, when diseased plants are found, remove them promptly and spread lime powder over the diseased area to control spread; fourth, in the early stage of disease, spray with 65% Zineb wettable powder at 500 times dilution.

(3) Rust Disease

On affected leaves, round or irregular green lesions initially appear, slightly sunken. Lesions on the underside of leaves are slightly raised, bearing rust-yellow raised gelatinous substances that, after rupturing, release large amounts of rust-yellow powder. Control methods: First, reduce field humidity; second, in the early stage of disease, promptly spray with 97% Fenaminosulf at 300 times dilution.

Market Prospect Analysis:

Corydalis Rhizome is a commonly used variety of traditional Chinese medicine. Its extract contains more than 20 kinds of alkaloids, with main effects of invigorating blood and dissolving stasis, regulating qi and relieving pain. Because its pain relief is non-addictive, it can also be used for late-stage cancer, similar in function to “Panax notoginseng”. Because Panax notoginseng is very expensive, Corydalis Rhizome, as its substitute, has continuously increasing market demand. As Chinese medicine products gradually begin to go abroad, overseas demand for Corydalis Rhizome is also continuously increasing. Total demand is about 20,000 tons or more, nearly twice the production volume.

In recent years, China's Corydalis Rhizome production and sales have both flourished, with prices stable and rising. As Corydalis Rhizome is used more and more widely in the pharmaceutical field, demand continues to increase, and market prospects are very broad. Corydalis Rhizome, together with Atractylodes macrocephala, peony, Fritillaria, etc., are known as the “Eight Flavors of Zhejiang”.