The invention relates to a medical bag which is intended for the infusion of a medicament by means of gravity. The inventive bag comprises: at least two compartments, namely a first compartment (1) containing a medicament in the form of a solution and a second compartment (2) containing a rinsing solution; and means for separating/communicating the compartments, which prevent the rinsing solution from automatically entering the medicament compartment except at the end of the infusion period. The rinsing solution ends the infusion, by rinsing the medicament bag and the infusion line, such as to prevent any risk of contamination or leakage of residual medicament from the bag or line.