Abstract : The main pitfalls regarding the use of sulphonylureas and metformin in type 2 diabetic patients are described and illustrated by a clinical case. Advices are given in order to avoid the occurrence of severe hypoglycaemic episodes with sulphonylureas and to minimise the risk of lactic acidosis with metformin. These drugs, when used appropriately with respect of contra-indications, have an excellent safety profile and remain the basis of the treatment of type 2 diabetes