Published clinical studies describing results from treating stroke patients with hyperbaric oxygen, performed at 11 different hyperbaric centers, were analyzed for benefit (a total of 265 patients). The cumulative amount of hyperbaric oxygen therapy (DHBOT) was calculated by multiplying chamber oxygen pressure (ATA) times the duration of each HBOT (in hours), times the total number of hyperbaric treatments. Efficacy of HBOT (EfHBOT) was computed from the number of patients in each study who showed significant clinical improvement of their neurologic status as a result of HBOT (percentage of the total number of patients who improved). The amount of benefit was compared with the total amount of HBOT. Analysis showed that benefit increased progressively as more treatments were given, as graphically depicted below.