Two cases of Wernicke's encephalopathy due to hyperemesis gravidarum are described. The first patient presented with bilateral papilloedema, altered sensorium and the second with bilateral retinal haemorrhages, ophthalmoplegia and nystagmus. Both patients were diagnosed with Wernicke's encephalopathy on clinical ground since there were no laboratory facilities to measure red cell transketolase and thiamine pyrophosphate levels. This is a rare but treatable complication of hyperemesis gravidarum (HG) and due to lack of diagnostic tools, there is often diagnostic uncertainty, delay in commencing appropriate treatment, as well as irreversible damage to the upper brain stem and death.