Research on the biochemical interactions among plants started in the former USSR and in Germany in late 1920s. Boris Tokin, a Russian embryologist, reported in 1930 that plant excretions contains substances which possess antimicrobial activity and termed them as Phytoncides. Later, Molish in 1937 published the first book on allelopathy and concluded that chemicals released by plants take part in plant interactions. Numerous scientists of the former USSR worked in allelopathy during 1960-90. This review summarises their most outstanding researches done in the world-renowned Soviet Scientific Schools lead by Boris Tokin, Andrei Grodzinsky and Valentina Roschina. The topics covered include investigations on Plant excretions, Biocenology, Ecology, Plant physiology, Biochemistry, Immunology, Pharmacology and Agronomy.