We studied 15 specimens of amoxicillin and 9 specimens of amoxicillin-clavulanic acid collected from pharmacies in Goma, DR Congo. Their claimed origin was India (n=11), DR Congo (n=5), France (n=4), Kenya (n=1), China (n=1), Germany(n=1), and Switzerland (n=1). The specimens were checked for falsifications following the WHO checklist. Content identity and amount of antibiotics in the specimens was investigated by Ultra High Performance Liquid Chromatography coupled with tandem mass spectrophotometry (UHPLC-MS/MS) and diode array detection (UHPLC-DAD). Nine of the 24 samples fulfilled the WHO criteria of counterfeit drugs, but all samples contained the active ingredients as claimed on the packages. We found under dosage of 90% and less in 3 of the 15 amoxicillin samples and in none of the 9 combined specimens. Amoxicillin over dosage (defined as 110% or more of indicated content) was found in 3 of the amoxicillin and in 1 of the combined specimens. Clavulanic acid was underdosed in none but overdosed in 5 of the 9 combined specimens. Our results highlight the need for drug quality control through inspection and specific analytical methods such as spectrophotometry and chromatography to reduce the public health challenge of illegal and substandard medicines in sub-Saharan Africa