What impact can mobile phones have on their users' health? Many individuals are concerned about the supposed ill effects caused by radiation from handsets and base stations, 1 the lack of credible evidence of any harm. But evidence for the beneficial effects of mobile phones on health is rather more 2 . Indeed, a systematic review 3 by Rifat Atun and his colleagues at Imperial College, London, gathers 4 of the use of text-messaging in the 5 of health care. These uses 6 three categories: efficiency gains; public-health gains; and direct benefits to patients by 7 text-messaging into treatment regimes. 　　Using texting to 8 efficiency is not profound science, but big savings can be achieved. Several 9 carried out in England have found that the use of text-messaging reminders 10 the number of missed appointments with family doctors by 26-39%, and the number of missed hospital appointments by 33-50%. If such schemes were 11 nationally, this would translate 12 annual savings of ￡256-364 million. 　　Text messages can also be a good way to deliver public-health information, particularly to groups 13 are hard to reach by other means. Text messages have been used in India to 14 people about the World Health Organization's strategy to control tuberculosis(肺结核). In Iraq, text messages were used to support a 15 to immunize nearly 5 million children 16 polio(小儿麻痹症). 　　17 , there are the uses of text-messaging as part of a treatment regime. These involve sending reminders to patients to 18 their medicine, or to encourage compliance with exercise regimes or efforts to stop smoking. However, Dr. Rifat notes that the evidence for the effectiveness of such schemes is generally 19 . More quantitative research is 20 —which is why his team also published three papers this week looking at the use of mobile phones in health care in more detail.