Context: Although several cases of intravenous (IV) injection of hydrocarbons with additives have been reported, no report to date has addressed IV isoparaffin intoxication. We describe the first case of chemical pneumonitis and subcutaneous necrosis after IV injection of isoparaffin (C12-C13, 99%) and we describe the chest computed tomography (CT) pattern of chemical pneumonitis after IV hydrocarbon injection. Case details: Following a suicide attempt by IV self-injection of 1 mL of solvent (isoparaffin, 99%) used in his workplace, a 23-year-old man presented with bilateral pleuritic chest pain. Chest CT showed multiple, peripheral, wedge-shaped, ill-defined ground glass opacities with consolidations in both lungs, and bilateral pleural effusion. The patient developed fever and cellulitis around the site of injection, later followed by subcutaneous necrosis. Treatment with antibiotics led to complete resolution of the symptoms and chest imaging findings. Discussion: Isoparaffin causes severe inflammation and necrosis in perivascular tissues. When injected IV, isoparaffin can cause chemical pneumonitis and acute lung injury, mimicking pulmonary infarction on chest CT because lung is the organ bearing the first capillary bed encountered. Concomitant subcutaneous necrosis may be associated with the extravasations. A favorable outcome with minimal residual pulmonary sequelae can be expected if the amount of injected isoparaffin is small.