We present an algorithm for solving the unification problem in the description logic $\mathcal{FL}_\bot$. This logic extends $\mathcal{FL}_0$ with the bottom constructor, and thus supports conjunction, value restrictions, top and bottom constructors. Unification of concepts can be a useful tool for ontology maintenance; however, little is known about unification even in small, restricted description logics. The unification problem has been solved only for $\mathcal{FL}_0$ and $\mathcal{EL}$. This paper contributes to the ongoing effort to extend these results to richer logics. Our algorithm runs in exponential time with respect to the size of the problem.