Chemotherapy stops or slows down the growth and proliferation of cancer cells. Chemotherapy usually uses in combination with, surgery, radiotherapy or other treatments. Therefore, it is useful to calculate the photon interaction parameters to determine the energy accumulation and penetration in tissue due to the interaction of cancer drugs with radiation. In this work, the mass attenuation coefficient (μ/ρ), half value layer (HVL) and effective atomic number (Zeff) of some cancer drugs (Tadocel, Fluro-5, Erbitux, Carboplatin, Temodal, Tamoxifen, Endoksan and Oxaliplatin) have determined experimentally at 13.81, 17.7, 26.34 and 59.54 keV photons emitted from Am-241-point source by using Si(Li) detector. Besides, we calculated theoretically the gamma-ray interaction parameters using the WinXCOM software program. Next to these, utilizing the GP fitting approach, exposure buildup factors (EBF) of the drugs determined up to 40 mfp in the energy range 0.015–15 MeV. Experimental and theoretical results have been found to be in harmony. Oxaliplatin and Carboplatin have larger μ and Zeff and lower HVL values than the other drugs under study. The smallest EBF values are observed for Endoksan, Oxaliplatin and Carboplatin for all of the penetration depths. Oxaliplatin, carboplatin and endoksan possess significantly good radiation absorbing effect. Keywords: Cancer, Drug, Mass attenuation coefficient, Exposure buildup factor, Photon interactions