  Transitions of the type $b \to s l^+ l^-$ are flavour changing neutral
current processes where new physics can enter in competing loop diagrams with
respect to the Standard Model contributions. In these decays several
observables sensitive to new physics, and where theoretical uncertainties are
under control, can be constructed. Particularly interesting are the angular
asymmetries in the decay $B_d \to K^* \mu^+ \mu^-$ and the measurement of the
branching fraction of the decays $B_{s,d} \to \mu^+ \mu^-$. Recent measurements
of these observables and the measurement of the isospin asymmetry in the decays
$B \to K^{(*)} \mu^+ \mu^-$ are presented.
