Lemierre's syndrome is characterized by thrombophlebitis in the internal jugular vein after an infection in the area of the head or neck, mostly in the form of pharyngitis and/or tonsillitis. It may also result from less common conditions, such as odontogenic infections, but this condition has not often been reported in the dental literature. The syndrome's main etiological agent is Fusobacterium necrophorum, and it most commonly occurs in young adults. This study reports the clinical case of a 34‐year‐old female patient of poor socioeconomic status with a history of pericoronitis, who reported having a chest pain that radiated to the upper limbs, along with dyspnea. The computed tomography of her neck provided evidence of an acute thrombus in the right internal jugular vein. The treatment comprised antibiotic and anticoagulant therapy in addition to the extraction of her third molar and some residual roots. This report highlights the perils of systemic complications through dental infection, including the risk of death.