Good’s zwitterionic buffers are widely used in biological and biochemical research in which hydrogen peroxide is a solution component. This study was undertaken to determine whether Good’s buffers exhibit reactivity toward H 2 O 2 . It is found that H 2 O 2 oxidizes both morpholine ring-containing buffers (e.g., Mops, Mes) and piperazine ring-containing zwitterionic buffers (e.g., Pipes, Hepes, and Epps) to produce their corresponding N-oxide forms. The percentage of oxidized buffer increases as the concentration of H 2 O 2 increases. However, the rate of oxidation is relatively slow. For example, no oxidized Mops was detected 2h after adding 0.1M H 2 O 2 to 0.1M Mops (pH 7.0), and only 5.7% was oxidized after 24h exposure to H 2 O 2 . Thus, although all of these buffers can be oxidized by H 2 O 2 , their slow reaction does not significantly perturb levels of H 2 O 2 in the time frame and at the concentrations of most biochemical studies. Therefore, the previously reported rapid loss of H 2 O 2 produced from the ferroxidase reaction of ferritin is unlikely due to reaction of H 2 O 2 with buffer, a conclusion supported by the fact that H 2 O 2 is also lost rapidly when the solution pH of the ferroxidase reaction is controlled by a pH stat apparatus in the absence of buffer.