Positive Coin is a participatory art project exhibited in Taiwan Contemporary Culture Lab (C-Lab) and Museum of Contemporary Art (MOCA), Taipei. “Positive” refers to HIV positive, and how HIV-positive people can bring positive meaning to their stigmatized disease. After consulting doctors, psychiatrists, and AIDS activists, our team designed a cryptocurrency with the bionic features of HIV. “How to kill the virus?”, “How to defeat the illness?” Susan Sontag depicts that we often use military vocabularies to describe diseases. As an artist, I gathered a team to compose the parallel analogies on the circulation of disease with trading. By combing the notion of currency with the disease, we also reverse the preconceptions on values.