For the Bi‐Pb‐Sr‐Ca‐Cu‐O (BPSCCO) system, a consistent set of data forTc, x‐ray diffraction, and scanning electron microscopy shows that Ag additions strongly react with BPSCCO to destabilize the 110 K superconducting phase, resulting in a strong depression inTcand lattice parameters when samples are treated in air or pure oxygen. This is in contrast to the behavior for the Y‐Ba‐Cu‐O and Bi‐Sr‐Ca‐Cu‐O systems, which do not show such degradation. However, Ag additions show no effects onTcand lattice parameters when samples are treated under low oxygen pressure. The formation of a low‐melting eutectic liquid with Ag2O‐PbO‐CuO solid solution affects the composition of the superconducting phase and degrades superconductivity, while the eutectic may be suppressed by reducing the oxygen partial pressure.