AbstractWe studied the induction of polyploid in Eucommia ulmoides, which produces trans-polyisoprene (EU rubber), and compared its hydrophilic low molecular metabolites and EU rubber contents with diploid. Seeds were submerged in 0.05% colchicine solution for 72 h. Ploidy levels were investigated by flow cytometry measurement and Giemsa staining. As a result, 15 tetraploids and 3 chimeras were selected from 144 seedlings. The characteristic morphological features of the tetraploid leaves were round shape, deep dentation, and dark green color. The hydrophilic low molecular metabolites in the leaves of the diploids and tetraploids were analyzed by gas chromatography-mass spectrometry (GC/MS). During principal component analysis (PCA) of the GC/MS data, the leaves were separated into two groups, and we concluded that some metabolites had changed due to chromosome doubling. However, there were no significant differences with regard to the content and molecular weight distribution of EU rubber.