Given its improved safety profile compared with systemic corticosteroids, propranolol has become the mainstay treatment of infantile haemangioma (IH) worldwide. There is evidence, mainly from adult volunteer studies, that propranolol use is associated with central nervous system (CNS) effects. Impairment to short‐ and long‐term memory, psychomotor function, sleep quality and mood with relatively low doses and durations of treatment have been reported. The exact magnitude of CNS effects resulting from propranolol use, especially in the early developmental stages and for prolonged periods of use, is not currently known. These effects may not be readily recognizable and require specialized assessment of cognitive function not routinely performed. Furthermore, there may be a delay between exposure and cognitive defects. The evidence to date provides a strong rationale to proceed with caution when prescribing propranolol for IH: treatment should be used only when indicated (in the presence of ulceration, impairment of a vital function or risk of permanent disfigurement) and for a limited duration, and the benefits of treatment should be weighed carefully against potential adverse events before treatment is initiated. This narrative review describes the evidence for an effect of propranolol use on CNS function from volunteer and patient studies, including IH.