By Chris Xia
East Asia editor, BBC News
A prominent critic of the Chinese government's record fighting HIV/Aids is being harassed by the authorities weeks after receiving a major award.
Dr Gao fought and won a battle to visit the US recently
Dr Gao Yaojie exposed a 1990s blood transfusion scandal that infected thousands of people in Henan province.
She was recently recognised for her work by a charity in New York, Vital Voices, sponsored by Hillary Clinton.
In the run-up to the event, she was prevented from applying for a visa, and in effect put under house arrest.
Only after an international outcry was she allowed to leave her house in Henan, and her country.
Now that Dr Gao has returned home, the BBC has learnt that she is once again under surveillance and her phone has been cut off.
Even the secret mobile phone she used to communicate with fellow activists has apparently been blocked.
A friend, Hu Jia, said the 80-year-old woman was in despair.
"She is in good spirits about her work, but after she returned from America, she found herself still in a very unpleasant situation, being harassed by the authorities and her children put under pressure.
"She feels pretty hopeless about the local authorities and her living conditions," he said.
Since Dr Gao brought the Henan blood transfusion scandal to the world's attention, she has continued to speak out about HIV/Aids in China.
Many of the issues she has identified have continued to present a very real risk for the spread of the disease in China.
Just this month, in the southern province of Guangdong, police broke up an unsafe blood-selling racket involving homeless people illegally donating blood for cash up to 15 times a month.
It is not thought they were screened for HIV or other diseases.