During exposure to cold, the body core temperature decreases more rapidly in individuals suffering from motion sickness (MS). In the present study we investigated the possibility to counteract this MS-induced predisposition to hypothermia by means of two drugs frequently used for the treatment of MS, i.e. the histamine-receptor blocker dimenydrinate (Amosyt®) and the muscarine-receptor blocker scopolamine (Scopoderm®). On seven occasions, 9 subjects were immersed in 15-degree water for a maximum of 90 minutes. Different combinations of drugs and placebo were given and, in four of the conditions, the immersion was preceded by motion sickness provocation. Motion sickness was found to increase the rate of core cooling (? rectal temperature). This MS-induced predisposition to hypothermia was prevented by Amosyt® but not by Scopoderm®, suggesting that the MS-induced predisposition to hypothermia is mediated by histaminergic rather than cholinergic neurons. As regards nausea, dimenhydrinate and scopolamine were equally effective, indicating that the MS-induced predisposition to hypothermia is not caused by the nausea per se. Consequently, the efficacy of a drug against nausea does not guarantee that it will also prevent the other autonomic dysfunctions induced by, for instance, the rocking of a life raft in rough weather.