  40 years have passed since the first molecular detection outside our Galaxy.
Since then, our knowledge on the distribution, kinematics and composition of
the molecular material in the extragalactic ISM has built up significantly
based not only on the carbon monoxide observations but also in the more than 50
molecular species detected. In particular, line surveys have been proven to be
excellent tools to study the chemical composition in the nuclei of galaxies.
Such studies have been favored by the increasing instantaneous bandwidth of
current mm and sub-mm facilities. Here I will summarize the highlights of
extragalactic molecular spectroscopy, mostly focusing in the results from
molecular line surveys published in the last few years as well as the aims of
still ongoing projects.
