Background: Paclitaxel is a cytotoxic drug belonging to the taxane family, widely used in medical oncology, such as in breast cancer, in which it has demonstrated great efficacy, whether as metastatic or adjuvant treatment. Paclitaxel's main toxicities are immediate anaphylactic reactions and peripheral neuropathy. The occurrence of idiopathic intracranial hypertension is an unusual event. The Clinical Case: This is a 53-year-old Moroccan woman, treated for breast cancer; she was put on sequential adjuvant chemotherapy after surgery. She received 3 courses of Doxorubicin and Cyclophosphamide without incident and then we started weekly Paclitaxel. From the very first courses, the patient presented with continuous but moderate headaches, and a cerebral Magnetic Resonance Imaging (MRI) showed signs of idiopathic intracranial hypertension, which was confirmed and treated in the neurology department. The patient progressed well, allowing the 12 courses of paclitaxel to be continued. Conclusion: Idiopathic intracranial hypertension is an unusual complication of paclitaxel. The occurrence of headache or other neurological symptoms in a patient being treated for breast cancer requires an urgent brain MRI, particularly to look for brain metastases.