Objective:To study excretion of ephedrines in human urine after oral administration of traditional chinese medicine Mahuang Tang decoction.Methods:After consuming a double clinical dose of Mahuang Tang decoction

urine samples from healthy volunteers were collected at different time.The urine sample and Mahuang Tang decoction were subjected to KOH（5 mol/L）alkalization and acetic ether extraction before gas chromatography-mass spectrometry（GC-MS）analysis.Results:The amount of NMP

NME

E

PE and ME in Mahuang Tang decoction was 4.38

3.24

97.45

26.15 and 6.16 mg

respectively.At 24 h post-administration

the average accumulated excretion rate of ephedrines were 118.84

291.96

70.18

90.74 and 38.10%

respectively.Conclusions:As one of the main active components of Mahuang Tang decoction

E excreted most quickly.ME excreted most slowly.NMP

NME

E

PE and ME were metabolites of Mahuang Tang decoction in human body.NMP

NME

E and PE mainly metabolized as unchanged parent compounds

while a small amount for ME

and then excreted in urine with assistance of kidney.