Graduate-level education in the health sciences builds from and is dependent upon knowledge supplied by prerequisite coursework. Such previously learned information may be stored well in memory without being readily accessible for application to facilitate new learning. Stored, but not retrievable information is termed “marginal knowledge”; psychology laboratory research has demonstrated that multiple-choice questions can be used to stabilize access to or “reactivate” marginal knowledge, even without feedback. Our study assessed whether this phenomenon was reproducible in an authentic classroom setting. One hundred and forty-five student pharmacists enrolled in the first-year Pharmacy Bridging Course (PBC) participated in this study, first completing a pre-course assessment comprising fill-in-the-blank questions about material covered in undergraduate prerequisites, but not to be covered in PBC. Students were then randomized to one of two groups to study three of the six lowest performance topics per the pre-assessment. After one week of PBC, students completed an interim assessment including study questions provided as fill-in-the-blank and then in multiple-choice format, without feedback. At the completion of PBC two weeks later, students repeated the pre-course assessment as a final exam. The interim multiple-choice test conferred better final exam performance on questions that students did not answer correctly on the pre-test, relative to the control condition (i.e., not taking the interim test; d = 1.03). In addition, the benefit of an interim multiple-choice question was significantly greater when students answered it correctly relative to incorrectly (d = 0.54). Interestingly, even incorrect responses on the interim test conferred a performance advantage over not taking the interim test (d = 0.61). Our study provides initial data to support that a multiple-choice test (even without feedback) in a genuine health professional classroom can produce a sufficient stimulus to stabilize marginal knowledge as demonstrated by improved retrieval of previously assessed material. We also know that this effect persists for at least two weeks as evidenced by the final exam performance; tracking this effect over longer follow-up periods provides an opportunity for further investigation.Doctor of Pharmac