We developed an English Collocations On Demand system offering on-line corpus and concordance information to help Japanese researchers acquire a better command of English collocation patterns. The Life Science Dictionary Corpus consists of approximately 90,000,000 words collected from life science related research papers published in academic journals. To make actual collocation problems clear, we compiled a learner corpus consisting of about 10,000,000 words taken from papers written by Japanese researchers in the same fields as the LSD corpus and compared the collocation patterns used by Japanese researchers with those used by native speakers of English. Some collocation patterns in the writing of Japanese researchers were found to be erroneous or deviating from natural English norms. Our system offers on-line information about collocations and collocates for any given English word and is therefore expected to help enhance the accuracy of learners' word selections and combinations. (Contains 3 tables and 5 figures.) [For the complete proceedings, "EdMedia 2012: World Conference on Educational Multimedia, Hypermedia and Telecommunications. Proceedings (Denver, Colorado, June 26-29, 2012)," see ED539862.]