AbstractIntroduction The dog is a frequently-used, non-rodent species in the safety assessment of new chemical entities. We have a scientific and ethical obligation to ensure that the best quality of data is achieved from their use. Oral gavage is a technique frequently used to deliver a compound directly into the stomach. As with other animals, in the dog, gavage is aversive and the frequency of its use is a cause for welfare concern but little research has been published on the technique nor how to Refine it. A Welfare Assessment Framework (Hall, 2014) was previously developed for use with the laboratory-housed dog and a contrasting pattern of behaviour, cardiovascular and affective measures were found in dogs with positive and negative welfare. Methods Using the framework, this study compared the effects of sham dosing (used to attempt to habituate dogs to dosing) and a Refined training protocol against a control, no-training group to determine the benefit to welfare and scientific output of each technique. Results Our findings show that sham dosing is ineffective as a habituation technique and ‘primes’ rather than desensitises dogs to dosing. Dogs in the control group showed few changes in parameters across the duration of the study, with some undesirable changes during dosing, while dogs in the Refined treatment group showed improvements in many parameters. Discussion It is recommended that if there is no time allocated for pre-study training a no-sham dosing protocol is used. However, brief training periods show a considerable benefit for welfare and quality of data to be obtained from the dogs' use.