A systematic review of substandard and falsified antimicrobials in selected East African countries (Ethiopia, Kenya, Rwanda, and Tanzania) found that 22.6% of 669 antimicrobial samples failed at least one quality test. Antibiotics accounted for 17% of failures, antimalarials for 24%, and anthelmintics for 56%. The most common quality control parameter assessed was API content, which was evaluated in 93% of studies. Fifty of the failing samples failed API content determination, while 26.5% failed visual inspection and packaging analysis. The study highlights the significant prevalence of substandard and falsified antimicrobials, which pose serious health risks due to ineffective treatment, resistance development, and potential harm to patients. The findings emphasize the need for improved regulatory frameworks, enhanced surveillance, and better quality control measures to combat the issue. The review also notes that many studies used non-random sampling methods, which may introduce bias. Overall, the results underscore the urgent need for action to address the problem of substandard and falsified antimicrobials in East Africa.A systematic review of substandard and falsified antimicrobials in selected East African countries (Ethiopia, Kenya, Rwanda, and Tanzania) found that 22.6% of 669 antimicrobial samples failed at least one quality test. Antibiotics accounted for 17% of failures, antimalarials for 24%, and anthelmintics for 56%. The most common quality control parameter assessed was API content, which was evaluated in 93% of studies. Fifty of the failing samples failed API content determination, while 26.5% failed visual inspection and packaging analysis. The study highlights the significant prevalence of substandard and falsified antimicrobials, which pose serious health risks due to ineffective treatment, resistance development, and potential harm to patients. The findings emphasize the need for improved regulatory frameworks, enhanced surveillance, and better quality control measures to combat the issue. The review also notes that many studies used non-random sampling methods, which may introduce bias. Overall, the results underscore the urgent need for action to address the problem of substandard and falsified antimicrobials in East Africa.