Introduction: M. pneumoniae is a respiratory pathogen, which commonly causes upper and lower respiratory infections. It primarily affects children and young adults. Respiratory symptoms are well recognised, but extrapulmonary involvement is also common. Other systems that have been implicated in the disease include: skin, mucus membranes, central, and peripheral nervous systems, cardiovascular, haematological, renal, musculoskeletal systems. Here, we report a case of an otherwise healthy, young female with M. pneumonia, who presented with right upper quadrant abdominal pain. Case presentation: a healthy 25-year-old female was referred to A&E by her general practitioner, after presenting with fever, malaise, and right upper quadrant pain. M. pneumoniae was confirmed retrospectively by serology. The patient made a full recovery after a six-day course of doxycycline 100mg. Conclusion: M. pneumonia is a well-established cause of respiratory infections in children and young adults. A febrile illness with multisystem involvement, even in the absence of respiratory symptoms, should raise suspicion of M. pneumoniae infection in healthy, young adults. Our case illustrates the multi-system involvement of M. pneumoniae, which was initially missed, due to paucity of respiratory symptoms at presentation.