Pressurized water extraction (PWE) was studied for the extraction of hydrolysable tannins from Phyllanthus niruri Linn. The effects of operating conditions (pressure, temperature, and the water flow rate) on the extraction yields were investigated. The results showed that the extraction yields increased with increasing temperature and with decreasing water flow rate, whereas pressure gave no significant effect. At 100bar, 100 degrees C and 1.5ml/min, the extract had higher component contents (%g/g extract) of gallic acid (0.65%), corilagin (4.11%), and ellagic acid (8.91%) than a commercial HEPAR-P extract (0.21%, 2.64%, 4.17%, respectively). It was also found that the dynamic PWE had a faster extraction rate and lower solvent consumption (0.018m3/kg) compared to the Soxhlet extraction and ultrasonication.