Compliance Aids have gained widespread use to assist patients in managing their medicines, with a view to addressing the issue of adherence. However, although patient outcomes may have been improved through better use of compliance aids, it has been highlighted that there are limited data on the stability of medicines, when removed from the original container and repackaged in a compliance aid. Exposure of medicines to heat, light, moisture and air (oxygen) may impact on both their chemical and physical stability, resulting in the potential for quality of the medicine and thus the safety for the patient being compromised. It is also uncertain whether the compliance aid can provide the same protection from these environmental conditions as the manufacturer's packaging, even though the time frame for repackaging is only 28 days. This paper presents a comprehensive review and detailed discussion of the available literature on the stability implications of repackaging medicines into compliance aids. The importance of repackaging is thus highlighted by its ability to impact on therapeutic outcomes for patients.