  The decay $D_s^+\to p \bar p e^+\nu_e$ with a proton-antiproton pair in the
final state is unique in the sense that it is the only semileptonic baryonic
decay which is physically allowed in the charmed meson sector. Its measurement
will test our basic knowledge on semileptonic $D_s^+$ decays and the low-energy
$p\bar p$ interactions. Taking into account the major intermediate state
contributions from $\eta, \eta', f_0(980)$ and $X(1835)$, we find that its
branching fraction is at the level of $10^{-9} \sim 10^{-8}$. The location and
the nature of $X(1835)$ state are crucial for the precise determination of the
branching fraction. We wish to trigger a new round of a careful study with the
upcoming more data in BESIII as well as the future super tau-charm factory.
