The composition of free amino acids and small peptides, especially non-protein amino acids and γ-glutamyl peptides, in higher plants have been surveyed in our laboratory. No systematic study on these constituents in plants of Polygonaceae, except buckwheat (Fagopyrum esculentum), has been reported. This paper deals with γ-glutamyl peptides and 3-(2-furoyl)alanine (probably an artifact) isolated from the roots of Rumex obtusifolius. Isolation of ascorbalamic acid is also described in relation to the presence of furoylalanine.