The amensalism of rice allelopathy has been applied to weed control, and great achievements have been made in the process. Rice allelopathy, defined by amensalism, has been on the research agenda for decades. Allelopathic autotoxicity, which can come about as a consequence of consecutive monoculture, has been shown to be a serious soil disease in plants, especially in consecutively cropped Chinese medicinal herbs, resulting in a decline in biomass and plant quality. Plant phenolic compounds are derived from cinnamic acid, which is formed from phenylalanine by phenylalanin ammonia lyase. Elucidation of the functional genes of allelopathic rice in regulating the adaptation of plants to stressful conditions will help develop a possible method of enhancing the allelopathic potential of rice using biotechnology. The degraded products of this process might play a key role in weed growth inhibition, which implies that plant allelopathy might result from plant–microorganism interactions in the rhizosphere.