The Chinese Academy of Medical Sciences celebrated its 60th anniversary last week. 60 is commonly symbolised by a diamond. The word diamond (Greek, adamas) means “unbreakable” and “unconquerable”. Fitting. Because thanks to the organisation of health care in China, the Chinese public has been the beneficiary of some remarkable successes. Indeed, “health” has increasingly been emphasised in government manifestos since 1954, according to research presented at the second Lancet–Chinese Academy of Medical Sciences Health Summit held in Beijing this week. In just one decade (2005–15), life expectancy for women rose from 75 to 80 years (for men, from 69 to 73 years). The Global Burden of Disease Study 2015 recently reported that in 1990 there were 29 922 maternal deaths in China. By 2015—within a single generation—that figure had fallen to 2948, a 90% reduction in preventable mortality. This progress is astonishing by any standards. But when I look through a file of press cuttings I keep on China, I can’t fully dispel some anxiety. Western media have reported President Xi Jinping's apparent efforts to bring China's “media to heel”. In February this year, according to The New York Times, President Xi said that, “All news media run by the party must work to speak for the party's will and its propositions, and protect the party's authority and unity.” The New York Times editorialised that, “each new effort to keep Chinese people ignorant about their government and the outside world will make them only more determined to learn”. In Chinese hotels, visitors may find a note to remind them that they lack access to, among other media, The New York Times. China has stable and enduring institutions that have achieved astonishing results for the health of its population. But how long can those institutions flourish while freedom to access global news and opinion is curtailed? How important is freedom of expression for China's future development? As a medical journal, we might argue that such freedoms are likely to be very important. The liberty to know and the freedom to speak enable scrutiny (and therefore accountability) of health policy. There is so much to admire about China's leadership and accomplishments in health. Is the sustainability of those outcomes in danger? China's health advances have prompted reflection about how to accelerate further progress. In January, the State Administration of Foreign Experts Affairs invited The Lancet to contribute to a discussion about how evidence of health systems reform might assist China's decision makers. We focused on the importance of deepening health reforms, focusing on primary health care, taking quality of care more seriously, upgrading the public health system, re-engineering the health workforce, seizing the moment for global health, and investing in science. The Global Burden of Disease Study matters because it helps to define priorities for China's health leaders. The leading causes of years of life lost are stroke and ischaemic heart disease. The importance of cancer, mental health, road injuries, hypertension, tobacco, and air pollution is reaffirmed. Obesity and diabetes are of growing importance. But such data tell only part of the story about China's health. A medical journal is like a barometer. We receive signals (for example, through letters) that are not always easy to measure by conventional means—in China, the health of migrant workers, challenges to providing health care in remote western regions, and the consequences of the new two-child policy. But there is one signal we should probably pay special attention to—namely, the breach of trust between China's doctors and their patients. Violence against health professionals has become a terrible wound in Chinese society. Its causes are many—commercialisation of health care, perverse incentives for medical professionals, and understandably rising expectations among the public. Our collaboration with the Chinese Academy of Medical Sciences is about showcasing the best Chinese medical science. It is also about helping to rewrite a covenant of trust between the Chinese public and Chinese medicine. At its best, science is about the commitment of scientists to serve society. Through their dedication to producing and disseminating new knowledge, and their vigorous engagement in public debate about the meaning of that new knowledge, China's medical scientists are playing an important part in renewing medicine's broken bond with the public. There may be wider lessons.