Background: A novel formulation of secnidazole is under development in the United States for the treatment of bacterial vaginosis (BV). Efficacy and safety of other formulations of secnidazole have been reported. The objective of this study is to evaluate the safety of a single-dose oral granule formulation of secnidazole in a U.S. population of women with BV. Methods: In this open-label study, patients were enrolled based on the following criteria: off-white, thin, homogeneous vaginal discharge; vaginal pH ≥4.7; presence of ≥20% clue cells; and positive potassium hydroxide whiff test. Eligible patients received a single dose of secnidazole 2 g at baseline. Patients were contacted on days 8-10 and were assessed for safety at an end-of-study visit (days 21-30). Additional endpoints included investigator assessment of the need for additional treatment and a post hoc analysis of clinical response to treatment. Results: Of 321 patients, 283 (88.2%) completed the study. The mean age was 32 ± 8.5 years; most patients were white (51.4%) or black/African American (46.1%). Most (79.1%) reported ≤3 episodes of BV in the past year. The overall number of treatment-emergent adverse events (TEAEs) was 95 (29.6%), of which 53 (16.5%) were treatment related. Common treatment-related TEAEs were vulvovaginal mycotic infection (5.3%), nausea (4.4%), and dysgeusia (3.1%). The proportion of patients not requiring additional BV treatment, as assessed by investigators, was 72.5%. Conclusions: Single-dose secnidazole 2 g was well tolerated, with a low overall number of TEAEs, most of which were mild to moderate.