The purpose of this study was to examine the chronic diuretic effect of the Bahirdhum Padhati Mashi (BPM) of unripe Cocos nucifera husk (Coconut husk) at different doses (100, 200 and 400 mg/kg) in normal rats. Daily oral administration of the BPM was tested for 4 weeks. Urinary water and electrolytes excretion were determined weekly. Oral administration of the BPM at different doses produced a significant and dose dependent diuresis and increase in electrolytes excretion. The highest dose (400mg/ kg) of BPM enhanced urine output from 10.20 ± 0.08 ml/24 h at the start to 23.25 ± 0.20 ml/24 h after the 4 weeks (p<0.001). It also produced significant increase in urinary excretion of Na+ (p<0.001), K+ (p<0.001) & Cl (p<0.001). Slight increase in glomelular filtration rate was also observed (p<0.001) for all the doses of BPM. It is concluded that the BPM of unripe coconut husk has a significant diuretic effect in rats.