Objective To explore the effects of ingestion of purified drinking water from water treatment devices on health of rats. Methods Under the same feeding conditions, the Wistar rats were divided into different exposure groups exposed to different kinds of drinking water such as electrolytic ion water (alkaline water), reverse osmosis water, middle hollow fabric filtered water, copper-zinc ally (KDF) filtered water, municipal water and source water respectively. The changes of the indexes including organ coefficient, routine blood test, blood biochemistry and electrolyte were observed at the 3rd and the 6th month of the exposure. Results Higher levels of the count of white blood cells and neutrophil, and higher concentrations of seralbumin and total albumin in serum were observed in rats of tap water group compared with those in control group (P