The aim of this article is to present the authors’ own method of using pentobarbital for premedication, anaesthesia or euthanasia of a snail, depending on the dose. Premedication and anaesthesia facilitate the procedures in studies using snails as laboratory animals. Different procedures, for example haemolymph collection and probing is much easier in anaesthetized animals. The research of the authors resulted in developing a complete procedure of drug administration directly to the circulatory system of Cornu aspersum maximum with high precision of dosing. C. aspersum maximum is a farm animal used as a source of meat in the food industry and can also be an alternative model for experiments requiring the use of animals. It is worth emphasizing that snails as invertebrates are not subject to the regulations of animal research ethics committees in the EU. However, it should be emphasized that it is a humanitarian method and as a way of premedication and anaesthesia-completely safe for animals.