The chemiluminescent behaviour of some indole derivatives in alkaline solution in the presence of Fe3+ was studied in detail. The effects of various kinds of surfactants and oxidants on the chemiluminescent reaction were studied. A flow injection system with chemiluminescent detection was developed for the determination of tryptophan, and the effects of some inorganic ions and basic amino acids were examined. Based on the results of treatment with the Hückel molecular orbital method and the investigations of fluorescent and absorption spectra, the relationship between structural characteristics and chemiluminescent behaviour is discussed, and a possible mechanism for this chemiluminescent reaction is proposed.