Background. Toxic substances may be inhaled or aspirated not always by patients themselves but sometimes byhealthcare providers unintentionally by nasogastric administrations or medications. Aspirated toxic particlesmay cause injury in the pulmonary epithelium at various levels of the respiratory tract, leading to a spectrumvarying from simple symptoms to severe chronic disease. Imaging features of substances are different dependingon their structure and are not well known. Moreover, on follow-up, radiologic findings are not well correlatedwith clinical findings which progress or recover more rapidly.Case. In this case series, we report three different chemical pneumonitis due to aspiration of exogenoussubstances of paint thinner, activated charcoal and liquid paraffin. We present three cases with chest radiographs,distinctive computed tomography findings and follow-up images.Conclusions. Aspiration of exogenous materials reveals typical imaging findings such as the metallic density ofcharcoals, fat attenuation of liquid paraffin and necrotic areas within consolidation in hydrocarbon poisoning.Recognition of imaging findings is very important for the diagnosis and characterization of toxic substances.