This study deals with grassroots informatisation of healthcare through examining an existing case of empathetic and spontaneous formation of an online community of a surgeon and his patients. He is a highly reputable surgeon as a specialist of a rare disease, and was committed to online provision of information about the disease and ways to cure it through setting up and operating a bulletin board system to enhance communication between him and his existing/potential patients. On the other hand, his patients set up bulletin board systems and blogs to share information about the diseases, treatment experiences, burdens, lives and the medical doctor's treatments among those who suffer the same disease and the surgeon, and an online community of them has spontaneously arisen. This online community based on empathy for other patients and the surgeon is an object of analysis of this study as a case of grassroots informatisation of healthcare. Interviews with a patient of the disease who develops and operates online community sites and with two patients who have been audience (read-only community members) of the sites she and the surgeon set up were conducted.