As mindfulness is increasingly being implemented and adapted, more knowledge about its effectiveness and working mechanism is needed. In a meta-review (a review of reviews) we found that the 8-week trainings MBSR (Mindfulness Based Stress Reduction) and MBCT (Mindfulness Based Cognitive Therapy) significantly improve anxiety, depression, and stress in a multitude of chronic diseases. For the working mechanism we assessed brain scans: a review and data from the Rotterdam Study show differences in activity, connectivity and structure in the prefrontal cortex, amygdala, and hippocampus, indicating that the training teaches a different automatic reaction pattern that is visible in the brain. Following the rationale that stress affects blood ...