Infusion systems and methods for infusing one or more drugs or other agents into the body of a human or animal subject. The system is programmed to take remedial action(s) upon sensing of a fault or error in connection with the infusion. In some embodiments, an agent may be infused through redundant flowpaths and, if a fault occurs in one flowpath, the system may respond by increasing flowrate through other non-faulting flowpath(s). In some embodiments, the fault may be a physiological reaction or symptom in the subject and the system may respond by adjusting or stopping flowrate(s) or one or more agents or changing the ratio of simultaneously infused agents.