By carefully analyzing the relations between operator methods and the
discretized and continuum path integral formulations of quantum-mechan
ical systems, we have found the correct Feynman rules for one-dimensio
nal path integrals in curved spacetime. Although the prescription how
to deal with the products of distributions that appear in the computat
ion of Feynman diagrams in configuration space is surprising, this pre
scription follows unambiguously from the discretized path integral. We
check our results by an explicit two-loop calculation.