This is the second in a series of articles that apply patent citation analysis techniques to pharmaceutical patents. Co-citation clustering was used to identify the core pharmaceutical technological competencies of Allergan, Inc. and the technology fronts that this company is advancing. The analysis covers all US pharmaceutical patents assigned to Allergan issued between 1981 and June 30, 1998. The pharmaceutical patents were further classified as new chemical entities (NCEs) and non-NCEs. The main conclusion is that Allergan has three core technological competencies in pharmaceuticals: compounds with retinoid-like activity, ocular hypotensive agents and furanones as anti-inflammatory agents. In each of these areas, the company has developed a significant number of inventions that are closely related to each other and build on each other. At this time, Allergan appears to be pursuing the areas of retinoids and ocular hypotensives with the most vigour.