Objective: To optimize partical size of Magnoliae Officinalis Cortex boiling powder

and investigate effect of the amount of water on decoction of this boiling powder. Method: Five kinds of particle size of Magnoliae Officinalis Cortex boiling powder were prepared.Contents of magnolol and honokiol in decoction were determined by HPLC

mobile phase consisted of methonl-water (30 : 70) with a flow rate of 1.0 mL · min-1 and detection wavelength was at 294 nm.With transfer rates of magnolol and honokiol

dry extract rate as indexes

effects of particle size and the amount of water on decoction of Magnoliae Officinalis Cortex boiling powder were investigated by single factor tests

and compared with traditional decoction of herbal pieces. Result: Particle size and water amount both had significant effect on compound content and dry extract rate in decoction of this boiling powder.Optimum preparation process was that particles must be all through 10 mesh sieve

and fine powder of 80 mesh sieve shall not exceed 20%.When boiling powder was decocted once with decoction time of 10 min

transfer rate of compound and dry extract rate of boiling powder (particles must be all through 24 mesh sieve

added 20 times the amount of water) were successively 5.1 and 2.5 times those in traditional decoction of herbal pieces (added 10 times the amount of water

decoction time of 50 min)

those of boiling powder (particles must be all through 10 mesh sieve

10 times the amount of water) were all 2 times those in traditional decoction of herbal pieces. Conclusion: Boiling powder of Magnoliae Officinalis Cortex boiling powder can save herbs and decoction time by comparing with traditional herbal pieces.