Oral administration of substances is a common procedure in scientific experiments using laboratory animals and typically is achieved in conscious animals by using the intragastric gavage technique. While highly effective, this method can be technically challenging particularly in small animals such as mice, and can occasionally cause esophageal or other injuries. More importantly, procedures associated with intragastric gavage including restraining and intensive handling of animals result in increased stress levels that can influence parameters under study, for instance glucose levels. Here I describe a method to voluntarily administer substances orally to laboratory mice minimising injury potential and stress. In this method, the drug is incorporated into artificially sweetened and flavoured jelly and given to mice that have been trained to eat the jelly. The method is exemplified for chronically treating mice with Rimonabant, but can also be applied to many other drugs, as well as oral glucose tolerance test.