Limnophila aromatica, commonly known as rice paddy herb, is an aromatic aquatic plant in the Plantaginaceae family. The genus name Limnophila derives from Greek limne (“marsh”) and philos (“loving”), referring to its preference for wet habitats, while aromatica comes from Latin, meaning “fragrant.” Native to Southeast Asia, particularly found in Vietnam, Thailand, Cambodia, and Laos, this herb was traditionally used both as a culinary spice and a medicinal plant in flooded rice fields and home gardens.

In traditional Southeast Asian medicine, Limnophila aromatica was used as a digestive aid, carminative, and cooling herb, believed to treat fever, indigestion, and inflammation. The leaves were often brewed into herbal teas or used as tonics for general health and detoxification. In modern use, it is a key culinary herb in Vietnamese cuisine, especially in soups (such as canh chua), salads, and fresh herb platters, where its flavor—similar to citrus and cumin—adds a distinctive brightness. Phytochemical analyses have revealed a rich content of flavonoids, essential oils (including limonene, β-caryophyllene, and linalool), and phenolic compounds that exhibit antioxidant, antibacterial, and anti-inflammatory activities.