The water celery, Oenanthe Javanica DC., is a perennial herb which mostly grows on a damp ground or a streamside. The water celery is widely distributed in Korea, Japan, china, Taiwan, Indonesia, Malaysia and the other countries. From ancient times, the water celery has widely been used for food or medicine. In herbal medicine, the water celery has a medical actions which are defervescence, diuresis, jaundice, edema, hypotensor, haematic, angiostasis, sthenia, appetizer. Recently, studies on the water celery are briskly being conducted. For example, studies on the morphologic property and classifications of origin of the water celery, studies on the chemical constituents of the water celery which contains vitamins, proteins and amino acids, studies on the bio activities of the water celery which contains flavonoids. However, there is not studies of hematological changes in dogs administrated the water celery until now. Consicontly, this study was conducted to observed the hematological changes in dogs administrated excessive amount of the water celery crude juice for a long period. In this studies, all dogs showed significantly decrease of the PCV and Hb, and increase of the WBC, GSH and reticulocytes, but did not significantly change in the RBC, MCV, MCHC and Met-Hb.