When individuals are asked to write or talk about personally upsetting experiences, significant improvements in physical health are found. Analyses of subjects' writing about traumas indicate that those whose health improves most tend to use a higher proportion of negative emotion words than positive emotion words. Independent of verbal emotion expression, the increasing use of insight, causal, and associated cognitive words over several days of writing is linked to health improvement. That is, the construction of a coherent story together with the expression of negative emotions work together in therapeutic writing. Evidence of these processes are also seen in specific links between word production and immediate autonomic nervous system activity. Implications for therapy and for considering the mind and body as fluid, dynamic systems are discussed.