ขี้เหล็ก (Khilek) / Siamese Cassia
Family: Fabaceae
Senna siamea, also known as Siamese Cassia or ขี้เหล็ก (Khilek), is a medium-sized tropical tree native to South and Southeast Asia. It is a well-known component of Thai herbal medicine and cuisine, prized for its detoxifying and mildly sedative properties. The young leaves and flower buds are commonly cooked and eaten as a vegetable.
Botanical Characteristics
This evergreen tree can reach up to 15 meters in height. It has evenly pinnate leaves with 8–12 pairs of oblong leaflets, and produces yellow flowers followed by long, flat pods containing seeds. The plant is hardy, drought-resistant, and thrives in full sun and tropical climates.
Use in Thai Traditional Medicine
In Thai herbalism, ขี้เหล็ก is classified as a cooling and detoxifying plant. It is believed to cleanse the blood, support liver function, and promote restful sleep. Decoctions made from leaves and flower buds are traditionally used for treating insomnia and digestive imbalance.
Culinary and Nutritional Uses
Young leaves and flower buds are boiled to remove bitterness and mild toxins, then eaten with chili paste or incorporated into curries known as แกงขี้เหล็ก (Kaeng Khilek). The cooking process neutralizes anthraquinones, leaving a rich, slightly bitter flavor appreciated in Thai cuisine.
Cultivation Notes
Senna siamea grows well from seeds or cuttings, preferring sunny locations and well-drained soil. It fixes nitrogen in the soil, making it useful for agroforestry systems. In the KBE Thai Medicinal Herb Garden, it is cultivated for both its medicinal value and its role as a sustainable shade tree.
Historical Context
Known in Ayurveda and Southeast Asian folk medicine, Siamese Cassia has long been valued for promoting relaxation and detoxification. Its enduring presence in Thai food culture connects daily nourishment with natural healing wisdom.
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.
