Paravertebral injections are commonly used for the treatment of chronic back pain despite the lack of evidence for their efficacy. Here, we report a case in which repeated paravertebral injections of local anesthetics, corticosteroids and botulinum toxin resulted in extensive abscess formation involving the entire paravertebral musculature descending to the level of the midthighs. These abscesses induced a systemic inflammatory response syndrome and required surgical drainage as well as broad-spectrum antibiotic therapy.