It is generally recognized that some crops do not thrive when cropped annually on the same field. This phenomenon has been named "Iyachi" in Japanese and used to be avoided by rotating crops on the soil. In this connection, phytotoxic compounds originating from crops themselves by excretion and decomposition of organic materials are regarded as one of the causal agents. A typical example affected by continuous cropping can be seen in the plant family Solanaceae such as eggplant and tomatoes. Therefore, we first attempted to survey phenolic compounds in the roots of eggplant (Solanum melongena L.). This paper deals with the isolation and structure elucidation of four phenolic amides, four other phenolic compounds and an aromatic amine occurring in the roots of eggplant. The phenolic amides were identified as N-trans-feruloyl tyramine (V), N-trans-p-coumaroyl tyramine (VII), N-trans-feruloyl octopamine (VIII) and N-trans-p-coumaroyl octopamine (IX). The three amides V, VIII and IX are new compounds. Furthermore, four phenolic compounds were identified as vanillin (I), isoscopoletin (II), ethyl caffeate (IV) and ferulic acid (VI). The aromatic amine was identified as p-aminobenzaldehyde (III).