A preliminary phytochemical screening of fruits of Anethum gruveolens L., Apium gruveolens L., Daucus curotu L., and seeds of Erucu sutiuu Mill., revealed the presence of volatile oil, sterols andlor triterpenes, carbohydrates and/or glycosides, tannins and flavonoids in the four entitled plants; Glucosinolates were detected only in Erucu seeds. Pharmacological evaluation of the aforementioned plants for diuretic activity has shown the ethanolic extracts of Erucu sutiua seeds and fruits of Anethum gruueolens, Duucus curotu as well as the volatile oils in the former two plants to produce an increase in urine flow in dogs. Volatile oil of Erucu seeds, significantly, increased Na', K+ and CI-excretion in urine, whereas Anethum gruveolens volatile oil significantly increased Na' and CIexcretion only.