Dinaline represents a group of pharmacologically active lipophilic substances with a relatively simple structure derived from N-acyl-o-phenylenediamine. It has been found to exhibit high antineoplastic activity in a series of slowly growing tumors such as chemically induced rat mammary and colorectal carcinomas, osteosarcoma C22LR and Brown Norway myeloid leukemia. The drug was inactive against many of the typically hypersensitive signal tumors, i.e. mouse leukemias P388 and L1210, sarcoma 180 and Yoshida sarcoma. Colon carcinoma cells exposed to dinaline demonstrate distinct but reversible changes in amino acid transport, protein metabolism, DNA synthesis and cell proliferation.