Green tea catechins have been reported to have multiple health benefits. To understand their metabolic and toxicological interactions in the human body studies need to be undertaken using stable isotope labelled compounds, but they can be time consuming and expensive. Using microreactor technology labelling catechins could be produced more quickly and at a reduced cost. This research reports on a 2-step synthesis of deuterium labelled epicatechin developed using microreactor technology for the production. (C) 2010 Elsevier BM. All rights reserved.