The Λ c decays into a multitude of different final states, according to the rules of weak decays. The decay into a proton, kaon and pion (each of them charged) is a favorite with experimenters as it is particularly easy to detect. It accounts for around 5% of all decays; around 30 distinct decay modes have been measured. Studies of these branching ratios enable theoreticians to disentangle the various fundamental diagrams contributing the decays and is a window on weak interaction physics.