Objective:To study the chemical constituents of Polygonum capitatum.Method: Compounds were isolated and purified repeatedly by silica gel

Sephadex gel

ODS C18 and MCI gel column chromatography.Their structures were identified by physical

chemical methods and spectral data.Result: Seven compounds were obtained form 80% ethanol extract of P.capitatum

and identified as tetracosane-1

3-diol（1）

（24R）-cycloart-25-ene-3β

24-diol（2）

emodin（3）

daucosterol（4）

1-O-butyl-β-D-mannopyranoside（5）

2-O-butyl-β-D-fructofuranoside（6） and 2-O-butyl-α-D-fructofuranoside（7）

respectively.Conclusion: Compounds 1

3

5 and 6 were obtained from P.capitatum for the first time.Compound 2 and 7 were obtained from Polygonaceae for the first time.