Detection of thermal hypoaesthesia, hyperalgesia, and paradoxical sensation significantly contribute to the diagnosis of polyneuropathy (PNP). There is controversy about the clinical usefulness of detected heat hypoalgesia. In 50 chronic alcoholic patients we compared the prevalence and diagnostic value of heat hypoalgesia (HPT) to that of cold (CT) and warm (WT) hypoaesthesia using a "Marstock" thermotest. Clinical examination revealed PNP in 56%, cold hypoaesthesia was present in 62%, warm hypoaesthesia in 24%, paradoxical thermal sensation in 10%, cold and heat hyperalgesia in 12%, and heat hypoalgesia in 22%. Only 1 patient (2%) presented with heat hypoalgesia but normal warm and cold thresholds; he reported paradoxical thermal sensation and had PNP. One patient suffered first degree burn injury from heat pain examination. Heat hypoalgesia contributed least to the diagnosis of polyneuropathy (HPT versus CT: P < 0.001). In patients with sensory loss, testing heat hypoalgesia bears some risk of burn injury. In contrast to thermal hypoaesthesia and hyperalgesia, it does not significantly enrich the diagnostic workup of alcoholic polyneuropathies.