Can you please tell me the organs/systems where chemotherapy has very minor activities?

Confusing question: Do you mean toxicities or anticancer activity? If you are asking about organs not affected by toxicity of chemotherapy, then i would say that there are many organs that are not affected(with rare exceptions) by chemotherapy. This includes lungs, bones and brain. Liver is quite resistant although mild enzyme elevations are of no consequence. Main organs affected are: blood, gut and skin(hair in.