Astra's purchase of Merck's share of the company's joint venture may represent an emotional overreaction to the Swedish company's earlier strategic timidity. Few mid-sized companies in the 1980s (Glaxo being a notable exception) were aggressive enough to use their drugs as currency for entering the US market and building a significant presence. Merck was able to take advantage of several of them--including Astra. Now with a warchest gleaned from DuPont's and Astra's repurchase of their joint ventures, Merck, facing its biggest challenges in nearly two decades, can fund a larger marketing effort, more research, or afford the kinds of expensive licensing deals it's heretofore resisted.