This research work examines the influence of thermal radiation on the flow of a reactive hydromagnetic couple stress fluid flowing through a passable channel under the drive of heat source. The analytical expressions for the momentum and heat transfer are obtained to find the entropy generation rate using the modified Adomian decomposition method (mADM). The results are correlated with previously obtained results in the bid to ascertain and verity the efficacy of the mADM and mostly for end users to be able to predict the safe and unsafe situations. In addition to that, the effects of thermal radiation and other thermophysical parameters on fluid motion, energy transfer and rate of entropy generation are shown and discussed in tables and graphs.