Not at all. It is now the norm rather than the exception, and the majority of matriculants take at least one gap year. Admissions committees care about what you did with the time, not that you took it.
A good gap year strengthens your weakest area. That might be a clinical job to build hours, a full-time research position, a post-bacc or SMP to lift your GPA, or a service program like AmeriCorps. The only version to avoid is a gap year with nothing to show for it. Used well, the time makes you a more mature applicant with a clearer story, which is exactly what schools want to see.