Cardamine diphylla (Michx.) A. Wood (syn. Dentaria diphylla Michx.) is a wild endemic perennial Brassicaceae found in Canada and the United States, with rhizomes used by First Nations of North America for food and medicinal purposes. Glucosinolates (GLs) are its secondary metabolites, whose hydrolysis products have health-promoting effects. In continuation of previous work, we investigated non-GL secondary metabolites of the C. diphylla rhizome. Here we report the isolation and structural elucidation of one new natural product, 5′-O-β-D-glucopyranosyl-dihydroascorbigen (1) from the methanol extract of C. diphylla rhizomes. In addition, we isolated and identified for the first time in the Cardamine genus the known 6-hydroxyindole-3-carboxylic acid 6-O-β-D-glucopyranoside (2). The structures of the compounds were elucidated using spectroscopic methods. From the methanol extract of Cardamine diphylla rhizome, 5′-O-β-D-glucopyranosyl-dihydroascorbigen (1) and 6-hydroxyindole-3-carboxylic acid 6-O-β-D-glucopyranoside (2) were isolated. This is the second report on the presence of a glucosylated indole ascorbigen in plants.