Elsholtzia ciliata, commonly known as Vietnamese balm, kinh giới, or xiang ru in traditional Chinese medicine, is an aromatic annual herb in the family Lamiaceae (the mint family). It is native to eastern Asia, including China, Korea, Japan, and parts of the Indian subcontinent, where it has been used as a culinary herb and medicinal plant for centuries. The genus name *Elsholtzia* honors the German naturalist Johann Sigismund Elsholtz, while the species epithet ciliata is Latin for "ciliate" or "fringed with hairs," a direct reference to the fine, hair-like structures found on the bracts surrounding its flowers. Historically, xiang ru has been a cornerstone of Traditional Chinese Medicine (TCM) during the summer months, often referred to as "the herbalist's summer herb," utilized to treat summer-heat conditions, promote sweating, and relieve edema.

The plant is an erect, branched annual typically reaching 30 to 60 centimeters in height, featuring opposite, lance-shaped leaves with serrated margins. Its most striking characteristic is the terminal, dense, spike-like inflorescence composed of numerous small, pale purple to white flowers. These spikes are densely covered in small, ciliate bracts, giving them a fuzzy appearance. The entire plant is rich in essential oils, which are released when the leaves or stems are bruised, producing a potent, refreshing aroma that is often described as a blend of mint, citrus, and a hint of camphor. Elsholtzia ciliata thrives in moist, open environments, including riverbanks, forest edges, and disturbed areas, often colonizing agricultural fields where it is considered a beneficial weed.

Elsholtzia ciliata is primarily utilized as a culinary herb, particularly in Vietnamese and regional Chinese cuisines. Its fresh, vibrant leaves are used as a flavoring agent in salads, soups, and spring rolls, where they provide a sharp, clean, minty-citrus note that cuts through fatty ingredients. In many rural communities, the fresh or dried leaves are brewed into a fragrant, caffeine-free herbal tea, which is consumed hot or cold as a cooling, refreshing beverage during the hottest months of the year. The herb's pungency is significant; therefore, it is often used in small quantities, either chopped fresh as a garnish or infused as a base for aromatic sauces and dipping broths.

Nutritionally, the herb is low in macronutrients but is a concentrated source of bioactive phytochemicals. Its therapeutic and aromatic properties are driven by a complex profile of volatile oils, primarily elsholtzia ketone and naginate ketone, which are responsible for its sharp, refreshing camphoraceous scent. The plant also contains various flavonoids, such as luteolin and apigenin, and phenolic acids, which contribute to its antioxidant and anti-inflammatory activities. In TCM, xiang ru is categorized as having an "acrid and slightly warm" nature, used specifically to "transform dampness" and "release the exterior." Modern research explores these compounds for their antimicrobial, antioxidant, and potential diuretic effects, validating its traditional use in managing heat-related metabolic imbalances.

Major ingredients derived from this food source include fresh aromatic leaves and stems, dried herbal tea blends, and essential oil extracts. Significant bioactive compounds associated with the source include **elsholtzia ketone**, **naginate ketone**, **luteolin**, **apigenin**, **rosmarinic acid**, and various monoterpenes like **limonene** and **p-cymene**.