The spleen plays an important role in the body's defense mechanism against microbial infections. However, trauma or diseases sometimes make removal of this important organ necessary, which predisposes patients to certain infections. This increased risk of infection and the underlying reason for the organ's removal both may affect the provision of dental care. This article reviews the structure and function of the spleen, conditions that may require its removal or cause its dysfunction, and provides considerations for dentists who care for asplenic patients.