We report on a patient with acute intermittent porphyria (AIP) who, during treatment with hypertonic glucose, developed peripheral neuropathy. Once haeme-arginate was started, the progression of the neuropathy was attenuated. This suggests that hypertonic glucose may be inadequate in preventing the development of neuropathy in a patient with porphyria. However, haeme-arginate, if started early, can attenuate the progression of porphyric neuropathy.