Bidens pilosa L. (Beggar’s Tick)

Bidens pilosa L., commonly known as Beggar’s Tick or Spanish Needle, is an annual herbaceous plant in the Asteraceae family. The plant has an upright stem, with a blunt quadrangular shape; lateral leaflets are elliptical or ovate-elliptical; the flowers lack ray florets and have tubular disc florets; the achenes are black, strip-shaped, and slightly flattened. The flowering period is from August to September, and the fruiting period is from September to November.

The earliest record of Bidens pilosa is found in the Li Shizhen Medical Encyclopedia, which describes it as follows: “It grows by the pond, with a square stem and leaves with branches. Its seeds resemble hairpins and stick to people’s clothes like needles. Northerners call it ‘ghost needle’.”

Originally native to tropical America, Bidens pilosa is now widely distributed across tropical and subtropical regions of Asia and the Americas. In China, it is commonly found in East, Central, South, and Southwest regions, typically growing near villages, along roadsides, and in wastelands. Bidens pilosa has a wide adaptability, strong drought resistance, and thrives in warm, humid climates. It prefers loose, fertile, humus-rich sandy soil or clay soil. The plant mainly reproduces through seeds.

Bidens pilosa is a commonly used herb in Chinese folk medicine. The entire plant can be used medicinally. According to the Compendium of Materia Medica, it has the effects of clearing heat, detoxifying, dispersing stasis, and reducing swelling. It is mainly used to treat symptoms like sore throat and injuries from falls. Bidens pilosa is also an ideal material for remediating heavy metal-contaminated soils. However, in agriculture, it is considered a harmful weed, competing with crops for water and nutrients, thereby reducing crop yield and quality. The seeds of Bidens pilosa have three to four barbed bristles at the tip, which easily stick to people’s clothes as they pass by, hence the plant is also known as “sticking grass,” a name that reflects this characteristic.

Botanical History

Origin of the Name
The earliest record of Bidens pilosa is found in the Li Shizhen Medical Encyclopedia, which describes it as follows: “It grows by the pond, with a square stem and leaves with branches. Its seeds resemble hairpins and stick to people’s clothes like needles. Northerners call it ‘ghost needle’.” The seeds of Bidens pilosa have three to four barbed bristles at the tip, which easily stick to people’s clothes as they pass by, hence the plant is also known as “sticking grass,” a name that reflects this characteristic.

Morphological Characteristics

Bidens pilosa is an annual herbaceous plant with an upright stem, reaching a height of 30-100 cm. The stem is bluntly quadrangular, hairless or sparsely covered with fine hairs on the upper part, with a base diameter of up to 6 mm.
The lower leaves of the stem are smaller, three-lobed or not divided, and usually wither before flowering. The middle leaves have wingless petioles 1.5-5 cm long, are trifoliate, with three leaflets, rarely pinnately compound with 5(-7) leaflets. The lateral leaflets are elliptical or ovate-elliptical, 2-4.5 cm long, 1.5-2.5 cm wide, with an acute apex, near-rounded or broadly cuneate base, sometimes asymmetric, with short petioles. The edges are serrated, with the terminal leaflet larger, long-elliptical or ovate-oblong, 3.5-7 cm long, with a gradually narrowing or near-rounded base, with 1-2 cm long petioles. The edges are serrated, hairless, or sparsely covered with fine hairs. The upper leaves are small, three-lobed or not divided, and lanceolate.
The flower heads are 8-9 mm in diameter, with peduncles 1-6 cm long (3-10 cm during fruiting). The involucre base is covered with fine hairs, with 7-8 bracts that are strap-shaped, slightly wider at the top, 3-4 mm long when flowering, extending to 5 mm during fruiting, with a herbaceous texture, with sparsely covered short hairs or almost hairless edges. The outer phyllaries are lanceolate, 5-6 mm long during fruiting, with a dry, membranous texture, brown on the back, with yellow edges. The inner phyllaries are narrower and lanceolate. The flowers lack ray florets, and the disc florets are tubular, about 4.5 mm long, with a corolla 5-toothed at the apex. The flowering and fruiting period is from August to October.
The achenes are black, strip-shaped, slightly flattened, ribbed, 7-13 mm long, about 1 mm wide, with sparsely scattered warty projections and bristles on the upper part. The apex has 3-4 barbed bristles, 1.5-2.5 mm long, with backward-facing bristles.

Main Varieties

White-flowered Bidens (Bidens pilosa L. var. radiata Sch.-Bip.): This variety differs from the common Bidens pilosa mainly in that the capitulum has 5-7 ligulate flowers on the edge. The ligules are elliptic to obovate, white, 5-8 mm long, and 3.5-5 mm wide, with a blunt or notched apex. It is found in East China, Central China, South China, and Southwest China, typically growing near villages, roadsides, and wastelands. It is widely distributed in tropical and subtropical regions of Asia and America.

Habitat

Bidens pilosa is found in East China, Central China, South China, and Southwest China, growing near villages, roadsides, and wastelands at altitudes of 50-300 meters. It is widely distributed in tropical and subtropical regions of Asia and America. The plant thrives in warm and humid climates and prefers loose, fertile, and humus-rich sandy or clay loam soils.

Distribution Range

Bidens pilosa is distributed in various regions of China, including Hebei, Henan, Shandong, Anhui, Jiangsu, Zhejiang, Jiangxi, Fujian, Taiwan, Guangdong, Hong Kong, Hainan, Guangxi, Hunan, Hubei, Guizhou, Yunnan, and Sichuan. It is also found in tropical and subtropical regions of Asia and America.

Medicinal Value

Bidens pilosa is a commonly used herbal medicine in Chinese folk medicine. It has a warm nature, a bitter taste, and is non-toxic. The whole plant can be used medicinally, with effects such as clearing heat, detoxifying, dispersing stasis, and reducing swelling. It is often used in the treatment of conditions such as enteritis and dysentery. Recent studies have found that this herb can effectively regulate blood pressure in both directions—lowering it in hypertensive patients and raising it to normal levels in hypotensive patients. Clinically, it is widely used as an antihypertensive agent. Using Bidens pilosa to lower blood pressure is not only safe and reliable but also avoids the side effects of sexual dysfunction associated with some antihypertensive drugs.

Flavor and Nature: Sweet, bland, bitter, slightly cold.
Meridians Entered: Liver, lung, large intestine.
Effects: Clears heat, detoxifies, disperses stasis, and reduces swelling. It is used for appendicitis, nephritis, cholecystitis, enteritis, bacterial dysentery, hepatitis, peritonitis, upper respiratory tract infections, tonsillitis, laryngitis, amenorrhea, burns, snake bites, traumatic injuries, skin infections, convulsions in children, and malnutrition.
Contraindications: Not suitable for pregnant women.

Effects

Anti-inflammatory: Polyacetylene compounds in Bidens pilosa can significantly inhibit mouse ear swelling induced by croton oil and rat paw swelling induced by egg white. They also reduce rat cotton pellet granuloma weight and significantly inhibit capillary permeability in mice and leukocyte migration in rats with acetic acid-induced inflammation. Flavonoid crystals in Bidens pilosa also have good anti-inflammatory effects.
Sedative and Analgesic: Intraperitoneal injection of small Bidens pilosa flower extract can significantly prolong sodium pentobarbital-induced sleep in mice, markedly reduce spontaneous activity, synergize with chlorpromazine, and antagonize amphetamine. The writhing test and hot plate test show some analgesic effects.
Digestive System: Subcutaneous injection of Bidens pilosa significantly reduces gastric juice secretion in rats, lowers gastric juice pH, and free acid concentration, inhibits the propulsion of charcoal in the mouse intestine, protects against experimental gastric ulcers in rats, and reduces the incidence of stress-induced ulcers in mice.
Anti-cancer: Various extracts of Bidens pilosa have inhibitory effects on HL60 and V937 leukemia cells cultured in vitro, with polyacetylene compounds being the most effective.
Lipid-lowering and Antithrombotic: Oral administration of a water extract of Bidens pilosa and small Bidens pilosa flowers significantly reduces cholesterol and beta-lipoprotein in male rats, and intravenous injection significantly inhibits experimental arterial thrombosis formation in rats.

Medicinal Prescriptions for Bidens pilosa

Treatment of Malaria: Use 300-450 grams of fresh Bidens pilosa. Boil in water, add one egg, and consume the soup.
Treatment of Dysentery: Take a handful of tender Bidens pilosa shoots. Boil in water. For white dysentery, add brown sugar; for red dysentery, add white sugar. Take the mixture three times.
Treatment of Jaundice: Use 15 grams each of Bidens pilosa and oak leaves, and 30 grams of pine needles. Boil and consume the decoction.
Treatment of Hepatitis: Use 45-60 grams each of Bidens pilosa and yellow-flowered cotton. Add 1000 ml of water, boil until it reduces to 500 ml, and drink multiple times a day until the decoction is finished.
Treatment of Acute Nephritis: Take 15 grams of Bidens pilosa leaves (finely chopped). Boil in water and cook with one egg and some sesame or tea oil. Consume once a day.
Treatment of Migraine: Use 30 grams of Bidens pilosa and three red dates. Boil in water and drink warm.
Treatment of Gastric Pain: Take 45 grams of fresh Bidens pilosa. Stew with 120 grams of pork, add a little wine, and consume before meals.
Treatment of Hematuria: Use 15-30 grams of fresh Bidens pilosa leaves. Boil in water and drink.
Treatment of Traumatic Injuries: Use 30-60 grams of fresh Bidens pilosa (half the amount if using dried). Boil in water, add 30 grams of yellow wine, and drink warm. Take once daily, usually for three consecutive days.
Treatment of Weak Limbs: Use a handful of Bidens pilosa. Boil in water and drink the decoction.
Treatment of Snake Bites and Insect Stings: Use 60 grams of fresh Bidens pilosa. Boil in water until reduced to half a bowl, drink warm, and apply the crushed residue to the wound. Repeat the process twice a day.
Treatment of Gas Gangrene: Wash fresh Bidens pilosa with boiled cold water and use the decoction for fumigation and washing.
Treatment of Bleeding Wounds: Crush fresh Bidens pilosa leaves and apply them to the wound.
For Cold and Fever, Sore Throat, Heat Detoxification, Intestinal Abscess, and Snake Bites: Use 30 grams of Bidens pilosa. Boil in water and drink. For acute simple appendicitis, combine with dandelion and Glechoma longituba; for snake bites, use 60 grams of fresh Bidens pilosa, boil, and drink. Apply crushed fresh leaves to the wound.
Treatment of Traumatic Lower Back Pain: Bidens pilosa has blood-activating and stasis-dispersing effects. For treating traumatic lower back pain, use 60-90 grams of fresh Bidens pilosa (30 grams of dried), with appropriate amounts of red dates, brown sugar, and yellow wine. Stew and drink the juice.
Treatment of Concussion: Can be used with blood-activating herbs like Angelica sinensis, Ligusticum chuanxiong, and Salvia miltiorrhiza. Additionally, Bidens pilosa can be used to treat fatigue, overstrain, and weakness, often combined with Agrimonia pilosa and red dates.