Abstract
Chronaximetric changes were observed in the radial nerves of a group of pregnant women taking diets which proved to be deficient in vit. B. These changes often preceded clinical and hematological evidence of vit. B deficiency. The degree of peripheral nerve change, as indicated by chronaximetric examination, coincided with the severity of clinical manifestations of deficiency. Improvement following vit. B therapy was observed chronaxi-metrically at the time that clinical improvement was recorded. The detn. of the strength duration curve of nerve and muscle is a sensitive method to detect early clinical signs of a vit. B deficiency.