หญ้าใต้ใบ (Ya Tai Bai)
Family: Phyllanthaceae
Phyllanthus amarus, commonly called Stonebreaker, is a small annual herb widely distributed throughout tropical regions. In Thailand, it is known as หญ้าใต้ใบ (Ya Tai Bai), meaning “leaf-under grass”—a name inspired by the distinctive way its tiny fruits form beneath the leaves. The plant has been used in Thai and Ayurvedic medicine for centuries to support liver function, detoxify the body, and treat urinary disorders.
Botanical Characteristics
This herb grows 30–60 cm tall with slender, erect stems. The leaves are small, oblong, and arranged alternately on branchlets resembling compound leaves. Minute greenish-white flowers develop along the underside of branches, followed by tiny capsule-like fruits. It thrives in moist, well-drained soil and partial sunlight, often sprouting naturally after rains.
Use in Thai Traditional Medicine
In traditional Thai herbalism, หญ้าใต้ใบ is used to cleanse the liver, reduce inflammation, and promote urinary tract health. Decoctions of the entire plant are consumed to relieve kidney stones, jaundice, and digestive imbalance. Its bioactive compounds, such as phyllanthin and hypophyllanthin, have been studied for their antiviral and hepatoprotective properties. Herbalists also use it as part of detox blends to reduce body heat and purify the blood.
Cultivation Notes
Phyllanthus amarus grows easily from seed and self-propagates in tropical conditions. It prefers light shade, regular watering, and slightly acidic soil. In the KBE Thai Medicinal Herb Garden, it is cultivated as a short-cycle herb under larger shrubs, contributing to the natural biodiversity of the collection.
Historical Context
The Stonebreaker’s reputation originates from traditional Indian and Thai medicine, where it was used to “break stones” in the urinary tract and gallbladder. Modern research supports its efficacy in supporting liver detoxification and viral defense. Its presence in the Thai pharmacopoeia highlights the continuity of ancient plant knowledge into modern herbal science.
Disclaimer: This information is provided for educational and historical purposes only. It is not intended as medical advice. Always consult a qualified healthcare professional before using any herbal preparation.
