Hello Dear. Glutathione is one of the major endogenous antioxidant produced by the cells, participating directly in the neutralization of free radicals and reactive oxygen compounds, as well as maintaining exogenous antioxidants such as vitamins C and E in their reduced (active) forms. Glutathione can be used as a supplement along with chemotherapy drugs but it itself cannot be a substitute for chemotherapy drugs. Just like we advise to eat more fruits like orange to boost anti-oxidants and Vitamin C in the body. But we cannot ask patients to just eat fruits without medications right? similar is he role of glutathione or any other immunity boosters. It can only be a preventive strategy but cannot be a sole curative strategy. Hope i have answered your question. Feel free to contact me if you have any more questions. I ll be glad to help you. All the best With warm regards Dr Sanjay Kini