Atherosclerosis in carotid arteries depends mostly on hemodynamic parameters, and any disturbances in pulsatile flows may alter the hemodynamic parameters extensively. Gas emboli are one such source that can hinder and disturb standard blood flow patterns and potentially lead to occlusions and ischemia. To understand how gas embolism affects carotid artery hemodynamics, numerical simulation of coupled Newtonian two-phase laminar flow with interface tracking are performed in an anatomical image-based geometry with flow conditions closely approximating physiological flows. Bubble behavior and Pulsatile flow field changes are quantified. Significant deviation from flow without gas embolism is observed leading to nonstandard flow distributions. Results show that gas embolism promotes complex spatio-temporal variations in the carotid artery hemodynamics leading to higher time averaged shear stress values and greater regions of high oscillatory shear index, implying higher probability of atherosclerosis incidence. Depending on contact angle, gas emboli were found to be lodged in carotid sinus or exiting the carotid artery, which can potentially cause abnormalities in blood pressures, heart rates, and ischemia in downstream vasculature, respectively.