  The cosmic origin of fluorine is still under debate. Asymptotic giant branch
(AGB) stars are among the few suggested candidates to efficiently synthesis F
in our Galaxy, however their relative contribution is not clear. In this paper,
we briefly review the theoretical studies from stellar yield models of the F
synthesis and chemical equilibrium models of the F-containing molecules in the
outflow around AGB stars. Previous detections of the F-bearing species towards
AGB and post-AGB stars are also highlighted. We suggest that high-resolution
ALMA observations of the AlF, one of the two main carriers of F in the outflow
of AGB stars, can provide a reliable tracer of the F-budget in AGB stars. This
will be helpful to quantify the role of AGB stars in the Galactic F budget.
