A clinical assessment of metrizamide (Amipaque) lumbar myelography in 150 patients is reported, and the adverse reactions encountered are presented and discussed. Minor adverse reactions--headache (48%), nausea (10%) and vomiting (7%)--were common, and the incidence reflected overseas experience. Severe headache occurred in a significant proportion of patients (20%), despite adequate hydration and the use of a small-gauge needle. There were no major adverse reactions such as epilepsy or severe muscle spasm. The study suggests that metrizamide is well tolerated, gives good anatomical demonstration and should replace iophendylate (Myodil) in this region. Recent reports of occasional, but sometimes severe, neurological complications indicate that further cautious assessment is required.