Click to expand Image Can Thi Theu in the dock during her appeal at the Hanoi People's Court, Vietnam, on November 30, 2016. © 2016 Vietnam News Agency/AFP via Getty Images Can Thi Theu, 64, is serving an eight-year prison sentence at Prison No. 5 in Vietnam’s Thanh Hoa province because she joined protests against land confiscation and environmental degradation in 2016 and publicly supported other human rights activists and political prisoners languishing behind bars. During a recent visit, Can Thi Theu’s family learned that she had been suffering from acute abdominal pain and fever for days. They said medical personnel at the prison told her it was nothing and gave her some painkillers. Her daughter, Trinh Thi Thao, filed a petition to allow Can Thi Theu to seek care at a hospital outside the prison.Can Thi Theu had a similar episode last summer and in January suffered from dizziness and tremors and could not walk without assistance for two weeks. In both instances, the prison authorities ignored her requests to have independent medical examination and treatment.Her sons, Trinh Ba Tu and Trinh Ba Phuong, are also serving long prison sentences for their peaceful activism. Can Thi Theu is among a number of political prisoners in Vietnam suffering from poor health. Tran Duc Thach, Nguyen Nang Tinh, and Phan Van Bach, all imprisoned for campaigning for democracy, have also fallen ill in Prison No. 5.This July, Tran Duc Thach’s wife filed a petition urging the authorities to allow her husband, who suffers from severe eye pain, to seek treatment at an outside hospital. Nguyen Nang Tinh’s wife meanwhile has said he suffers from osteoarthritis and severe nerve compression and is in great discomfort.During a visit in February, Phan Van Bach’s wife said he suffered from severe tooth pain and has subsisted on congee (rice porridge) for more than a year. He felt “chest tightness, shortness of breath, and unsteady gait.” He also told his family that prison guards pepper-sprayed him and another prisoner beat him for protesting prison conditions.The United Nations Standard Minimum Rules for the Treatment of Prisoners (the Nelson Mandela Rules) provide that “[a]ll prisons shall ensure prompt access to medical attention in urgent cases. Prisoners who require specialized treatment or surgery shall be transferred to specialized institutions or to civil hospitals.”Vietnam’s international trade partners and donors should press the Vietnamese government to immediately release Can Thi Theu, Tran Duc Thach, Nguyen Nang Tinh, and Phan Van Bach, and allow them to seek adequate medical care at home or abroad.