In its attempt to liberate the hostages in Moscow, the government used a gas or vapour. Classical war gases are not appropriate for such a task because they cause irreparable damage, while inhalation anaesthetics are inappropriate because they take too long to take effect, and because hundreds of litres would have been required for a sufficient effect. Following the liberation of the hostages, it was reported that a fentanyl derivative had been used, most likely carfentanyl. From the way that the hostages, in Moscow were liberated, it is clear that terrorist attacks in which chemicals are used may also take place in the future in the Netherlands. In order to be able to react adequately to such situations, additional training for physicians and other health-care personnel is urgently necessary and the hospitals must also be better prepared for this task, especially for the artificial respiration of large numbers of patients and for the administration of large amounts of antidote in easy-to-use dosage units. From now on, on-site treatment and stabilisation will not be reserved only for trauma cases.