Treatment of patients often includes the administration of medications and 
sometimes radiation. While the intent is to treat an underlying condition, in 
some cases, adverse effects occur due to these agents. Most of these adverse 
effects are mild, however, some can be severe and life-threatening. Furthermore, 
while these effects are often reversible upon cessation of exposure, especially 
if the inciting agent is recognized and withdrawn early, others might be 
permanent or even progressing. Most common histopathologic findings in 
drug-induced interstitial lung disease include nonspecific interstitial 
pneumonia (cellular and/or fibrotic), organizing pneumonia with or without 
bronchiolitis, eosinophilic pneumonia, pulmonary edema, diffuse alveolar damage, 
hypersensitivity pneumonitis, granulomatous interstitial lung disease, chronic 
bronchiolitis, and pulmonary hemorrhage. Pulmonary vascular changes or 
constrictive bronchiolitis can also occur. Drugs that are more commonly 
associated with lung toxicity include nitrofurantoin, amiodarone, and 
chemotherapeutic agents such as bleomycin and methotrexate. More recently 
introduced immune modulating agents including rituximab and immune checkpoint 
inhibitors such as anti-CTLA4, anti-PD-1 and anti-PD-L1 agents have also been 
associated with adverse effects in the lung. Radiation therapy to the chest can 
trigger acute or chronic lung toxicity. While newer radiation techniques are 
aimed to decrease and minimize side effects other risk factors such as 
additional chemotherapy, oxygen, and older age may be rising. Foreign substances 
such as talc, hydrogel, and medical devices such as hydrophilic polymer coated 
catheter may rarely also lead to pulmonary complications. It is important that 
clinicians and pathologists are aware of these potential adverse effects of 
drugs, radiation and medical devices and raise the possibility of drug-induced 
lung toxicity after exclusion of other differential diagnoses. It is the role of 
the clinician to provide the pathologist with an appropriate drug history. Early 
intervention to a drug-induced lung toxicity might prevent progression of side 
effects and permanent changes.