The structured floral arrangement (SFA) program was developed for cognitive rehabilitation and mental health care. This program required participants to create symmetrical floral arrangements as per predetermined procedures and with instructions given on the sequence of placing each natural material. Attentional deficit, particularly unilateral spatial neglect, nearly disappeared after SFA intervention for a patient with traumatic brain damage. This positive effect was maintained for five months. In schizophrenic patients, visuospatial working memory was improved after SFA intervention. Motivational rehabilitation also increased through the SFA program. This program for mental health care was implemented for participants suffering traumatic stress from the Great East Japan Earthquake of 2011. The number of participants who showed mild physical symptoms (e.g., headache) decreased from seven to just one after SFA intervention. These findings suggest that the SFA program has the potential to improve brain function and/or mental health.