A change in the color of their pills could make it less likely that they will be taking their medication

The researchers said that while the color of the pills rarely changed, it depended on who was filling up the prescription. According to the study, around 11,500 people did not fill their own prescriptions of which 1.2 percent had the color of their pills changed. The study has been published in the journal JAMA Internal Medicine.
“Patients fill medications multiple times a year... The chance of these changes happening gets to be much higher. If they are taking nine medicines, they get at least 36 'opportunities' a year to experience a color change. This seemingly small risk then starts to appear very substantial”, Dr Kesselheim said.
Source-Medindia