  We present constraints on products of two leptoquark (LQ) coupling constants.
The bounds are obtained from meson decays, in particular leptonic \pi, K, D,
D_s, B, B_s decays. Furthermore semileptonic meson decays and mixing in neutral
meson systems are discussed. We use the Buchmueller-Rueckl-Wyler-model for
scalar and vector LQs. Bounds on R-parity violation can be extracted directly
from the corresponding LQ bounds. Our results are listed in the Tables 6 (for
LQs) and 7 (for SUSY particles) with english captions. The bounds of
Davidson/Bailey/Campbell were updated. The SUSY-bounds of
Dreiner/Polesello/Thormeier were reproduced.
