Supplementary file 1_Colour of medicines and children’s acceptability: What children think of the colour of oral dosage forms?.docx

BackgroundColour plays an important role in shaping consumer experiences, and in the context of medicines, it may influence patients’ expectations, behaviours, and treatment adherence. There is limited research on how children respond to medicine colour, despite their increased sensitivity to sensory cues. A previous literature review indicated that colour may affect medicine acceptability in children but highlighted the need for further research. This cross-sectional study aimed to fill that gap by directly collecting children’s opinions on the colour of oral medicines through an online survey, targeting a diverse paediatric population across age, health status, and countries in Europe.
MethodsThe survey, developed by UCL School of Pharmacy UCL REC (ID 26765/001) and reviewed by experts of the European Young Persons Advisory Group Network (eYPAGnet), was translated into five languages and distributed via QR codes and anonymous links. Response collection occurred between September 2024 and April 2025. Participants included children aged 3 to 18, with parental assistance when needed and parental consent. Responses were analysed using the software R Studio.
ResultsOut of 669 people who accessed the survey, 382 completed it. For liquids, pink (23%), colourless (16.5%), and blue (15.2%) were most preferred. Reasons included appealing look and taste associations (e.g., strawberry for pink). For solids, white (29.1%), pink (18%), and blue (12.5%) led, with neutral appearance and berry-related flavours cited. Statistically significant gender and age differences in preferences emerged, while variations by health, or country were not always significant. Ratings for previously used medicines highlighted preference for purple, pink, and blue, while white and colourless received moderate scores. A statistically significant link between taste and colour emerged (ρ = 0.42, p-value 2.2 × 10−16), suggesting that the colour of a medicine may influence children’s anticipation of its taste and shape their overall expectations of the treatment experience.
ConclusionThis study offers valuable insight into children’s preferences for medicine colour. Pink and blue were associated with sweet/flavourful tastes, while neutral colours were perceived as tasteless, particularly by participants aged 12–18 years. These findings can inform paediatric formulation strategies, particularly the selection and use of colouring agents, in alignment with current regulatory requirements when their inclusion is considered necessary.