The objective of this work is to demonstrate the quality of Ampicillin used alongside and in the health centers by the population of Niamey city by using Thin Layer Chromatography method to compare the results achieved in order to contribute to informed decision-making for possible interventions. This comparison aimed to investigate the quality of on eleven samples distributed as follows which five samples are from pharmacies, five samples are from street vendors and one sample specialty used as reference to check the quality control of them. The different reagents used are: Hydrochloric acid (HCl) 32-36%, acetone, distilled water, ethyl acetate and acetic acid. All samples migrated in proposed diluent. This shows that all samples contain the active ingredient substance of ampicillin. The percentage of the active ingredient were calculated as per protocol of Clarke’s analysis of drugs and poisons in chemistry guidelines. It varies from 89,46 to 94,73 for pharmacies and street vendors.According to the results of the different frontal reports, sixty percent of Ampicillin products purchased from each side contains the percentage of active ingredient recommended by WHO.This technique of quality control can be used for practical work or tutorial and laboratories where drug quality control mechanism is not often checked.