A 70-year-old woman who had suffered from aseptic meningitis complained of chronic headache after dental treatment including tooth extraction. She developed a fever and respiratory failure. Based on chest computed tomography and head magnetic resonance imaging (MRI), she was diagnosed with osteomyelitis in the clivus accompanying moderate pituitary involvement, cavernous sinus thrombosis and septic pulmonary embolism. Both of the causal bacteria, Fusobacterium nucleatum and Campylobacter rectus, were isolated from her blood. Dual infection leading to clival osteomyelitis and cavernous sinus thrombosis has not been reported. It is important to perform enhanced MRI and blood culture for patients with chronic headache related to dental treatment.