A pale green, small-leafed herb native to Southeast Asia where it grows in hot, high-humidity environments, such as rice paddies. Rice paddy herb goes by various names including ngo om, phak khayang, seui fa and shui fu rong. It has a flavor suggesting citrus and cumin and an undertaste some describe as soapy. Rice paddy herb is primarily found in Vietnamese dishes such as canh chua ca (a hot and sour fish soup), as an accompaniment to pho and in curries. Its growing environment makes it hard to find outside of Southeast Asia, though some Vietnamese markets carry it.
From The Food Lover's Companion, Fourth edition by Sharon Tyler Herbst and Ron Herbst. Copyright © 2007, 2001, 1995, 1990 by Barron's Educational Series, Inc.