AbstractThirty‐five patients out of the 2,000 PCB‐poisoned cases that occurred in central Taiwan in 1978 were neurologically studied in 1980. Neurological manifestation included clinical peripheral sensory neuropathy in about two thirds of the cases, headache in two‐fifths and dizziness in one‐third. There was no relationship between the blood PCB concentration in patients with neurological manifestation and those without. Sensory nerve conduction velocity was reduced in about half of the cases and motor nerve conduction was delayed in about one‐third of the cases, which suggested that PCB poisoning apparently affected not only sensory nerve conduction but also motor nerve conduction. Normal CSF PCB concentrations (0.5–2.3 ppb) indicated that PCB had difficulty penetrating the blood‐brain barrier. A mildly abnormal EEG pattern was found in one fifth of twent