Some 49 reactions involving compounds of the type HxOy have been examined in terms of their possible significance to stratospheric and mesospheric chemistry. Of this set of 49, some 20 processes were evaluated to be of potential importance. Within this subset of 20, the rate constants for 8 of these reactions were indicated as either having undergone a significant reevaluation within the last 2 years or were due to be reevaluated based on new data. A discussion of new experimental data resulting in these reevaluations is presented. Finally, recommendations are made as to the need for new experimental work.