  We study the formation of Li lines in a case study of an S-type AGB star in
the SMC. AGB stars may be important providers of $^7$Li to the interstellar
medium. Abundance analysis of these stars is difficult due to the heavy
molecular blanketing, uncertainties in the model atmospheres and possible
departures from LTE in the Li atomic level populations. We address here the
latter problem and somewhat also that of background molecular line formation.
We do not find non-LTE effects big enough to alone rule out the possibility
that the reported super-Li-rich stars exist. There are, however, several other
complications connected to the formation of the Li lines in these stars.
