5-Ethynyl-2’-deoxyuridine is an extensively used nucleoside analog used as a probe for DNA synthesis. 5-Ethynyl-2’-deoxyuridine is known as an toxic anti-metabolite, which potentially causes DNA instabiliy, necrosis and cell-cycle arrest, therefore it is often used for short-term DNA synthesis in tissue culture and living organisms where prolonged cell survival is not required.