“…In some of these studies, medication waste was returned by patients to community pharmacies, general practitioners’ clinics, hospitals or sometimes collected via medicine take-back and medicine waste campaigns. However, twenty nine (the majority) studies used a survey to collect information about the therapeutic classes and dosage forms of medication waste by asking participants for information without physically collecting the waste: six studies from Ethiopia [ 36 , 37 , 38 , 39 , 40 , 41 ], three from India [ 42 , 43 , 44 ], two from Malaysia [ 24 , 45 ], two from the USA [ 34 , 46 ], two from Jordan [ 47 , 48 ], two from Egypt [ 26 , 49 ], two from Thailand [ 20 , 50 ], one from Qatar [ 51 ], one from China [ 52 ], one from Iraq [ 53 ], one from Indonesia [ 54 ], one from Nigeria [ 55 ], one from Spain [ 56 ], one from Saudi Arabia [ 27 ], one from Tanzania [ 57 ], one from Malta [ 58 ], and one from Ghana [ 59 ]. The methodologies used and the targeted populations are summarised in Appendix A Table A1 .…”