Zhu Ling (Chinese: 朱令; pinyin: Zhū Lìng, 24 April 1973 – 22 December 2023) was the victim of an unsolved thallium poisoning case in Beijing, China. In late 1994, while studying chemistry at Tsinghua University, she was poisoned; she subsequently fell into a coma in 1995. Her symptoms were posted online via a Usenet newsgroup by her friend Bei Zhicheng from Peking University, and were reviewed and diagnosed by physicians around the world. Although Zhu’s life was saved, she suffered severe neurological damage and permanent physical impairment. The investigation was closed in 1998 for lack of evidence and went cold until it drew renewed public attention in the 2010s, becoming one of the most high-profile cases in China and giving rise to widespread speculation and conspiracy theories.
Poisoning
First hospitalization In 1994, Zhu Ling was a sophomore in Class Wuhua 2 (Class 2 majoring in physical chemistry) at Tsinghua University in Beijing. Classmates described her as attractive, intelligent, and musically talented. She began to show strange and debilitating symptoms on 24 November 1994, when she reported acute abdominal pain, and loss of appetite. On 5 December she again experienced stomach discomfort, and her hair began to fall out. On the night of 11 December 1994, despite her illness, Zhu Ling insisted on performing with the Tsinghua University Chinese Orchestra at the Beijing Concert Hall, where she played a Guqin solo of the piece "Guangling San." She had to wear glasses because her eyes were painful and at times she could not see at all. Her hair fell out completely within a few days of the performance. Zhu was admitted to Beijing Tongren Hospital on 23 December 1994. Her condition gradually improved, she was allowed to return to school, and she was discharged on 23 January 1995.
Second hospitalization A new semester began on 20 February 1995. On 27 February, shortly after returning to school, Zhu experienced intense pain in both legs. Her condition deteriorated further on 6 March, with severe leg pain and dizziness, and her parents took her to Peking University Third Hospital for treatment. Professor Chen Zhenyang (陈震阳), who was involved in her diagnosis and treatment, recorded in his paper "Introduction to a Rare Case of Severe Thallium Poisoning" that on 8 March Zhu "once again experienced intense foot pain, pain in the calves, so severe that she dared not touch any objects. This time it was more severe than the before, and the condition developed rapidly, extending to the lower back." On 9 March 1995, Zhu Ling's parents took her to the neurology clinic at Peking Union Medical College Hospital (PUMCH). After examining her, Professor Li Shunwei (李舜伟), told Zhu's mother that her condition was "very similar to a case of thallium poisoning at Tsinghua University in the 1960s." In the medical record for that day, Li described Zhu's condition as follows: "(the patient is) mentally clear and articulate, experiencing significant hair loss, limbs hurt by touching, redness at the fingertips and soles which are not swollen but with elevated temperature. Reduced sensation in the fingertips and below the knees, with a symmetric knee reflex. Ankle reflex is slow. Highly suspicious of heavy metal poisoning, such as thallium and beryllium, consulted with Director Zhang Shoulin and professors, including Ding Maobai. On admission, Zhu "had clear Mees' lines on her fingernails, raising suspicion of possible thallium poisoning". To clarify the diagnosis, Li contacted Professor Zhang Shoulin at the Chinese Academy of Medical Sciences. That same day, Zhu, accompanied by her mother, was examined by Zhang, who suspected acute thallium or arsenic poisoning; the institute, however, was unable to conduct the necessary tests. Zhu denied any contact with thallium in class, a claim confirmed by Tsinghua's chemistry department. PUMCH also cited a lack of equipment to perform such tests, and so–at the hospital where the future suspect Sun Wei's mother worked—no thallium test was carried out.
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