In a prospective study over 12 months, serum C-reactive protein concentration was measured serially in 20 consecutive patients who underwent therapeutic embolisation for various forms of malignancy and in 13 patients who had diagnostic coeliac or hepatic angiography without embolisation. All the patients who underwent successful embolisation showed a C-reactive protein response and in all cases the height of the response correlated well with the estimated size of the embolised tumour. Patients who recovered uneventfully showed a prompt fall in C-reactive protein from its peak values towards normal. In contrast, patients undergoing angiography alone showed only a minor increase in C-reactive protein concentration unless there were intercurrent complications. These results, together with the commercial availability of rapid and precise assays for C-reactive protein, indicate that serial measurement may be useful in the confirmation of tissue necrosis and assessment of its extent; also in the recognition of intercurrent complications following therapeutic embolisation.