The Car-Parrinello molecular dynamics 1 (CPMD) method has proven itself to be one of the most successful techniques in elucidating important chemical phenomena. In a previous study we performed an exhaustive study of the possible chemical reactions that can occur when guanine interacts with an OH radical in the gas phase3 We first examined all possible reactions of thymine with an OH radical in the gas phase with both CPMD and static quantum chemical mechanisms. Through WC analysis we find that sigma-electron loss is responsible for the hydrogen atom transfer to form a thymine cation radical and water. We also performed reactions of the aforementioned DNA bases in the presence of explicit water. Our results here will be discussed as well as a comparison to calculations performed with static quantum chemical solvent models.