The nitrogen content which is soluble in many kinds of solvents, in fresh and dried leaves of Russian comfrey was investigated. Harvest periods of Russian comfrey are in the latter part of May and in the early part of September. Ratios of H 20 and 0.3% NaOH soluble nitrogen are increased and 10% NaCl soluble nitrogen decreased in dried leaves compared to fresh leaves. These tendencies are observed in protein nitrogen fraction of dried leaves. The variation of solubility is considered to be caused by denaturation of protein. NH3-N, N03-N, NH 2-N, Amide-N, and Peptide-N are determined in dried leaves, and some considerations of these nitrogenous compounds, especially nitrate poisoning effect on livestock, are issued.