Caution: Patient-specific preoperative preparations combined with procedure-specific 5-aminolevulinic acid may lead to critical events.

5-Aminolevulinic acid (5-ALA) is orally administered 2-4 hours before surgery to identify tumor location. Hypotension is sometimes observed after 5-ALA administration. Case reoprt We present a case of a patient with 5-ALA-induced hypotension that resulted in the development of cerebral infarction. An 83-year-old man with a bladder tumor was scheduled for photodynamic diagnosis-assisted transurethral resection of bladder tumor (PDD-TURBT) and right radical nephroureterectomy. 5-ALA was orally administered and his ordinary antihypertensive and antianginal agents were also administered an hour after 5-ALA administration. Following this, his blood pressure dropped, and he developed muscle weakness and paralysis in his left upper extremity. Magnetic resonance imaging showed evidence of cerebral infarction. Conclusions We cannot conclude definitively that our patient's cerebral infarction was solely caused by 5-ALAinduced hypotension because hypotension under these circumstances is not rare. We consider that additional factors, such as patient-specific doses of antihypertensive and antianginal agents may have played a role in the development of his cerebral infarction. [ABSTRACT FROM AUTHOR]