Multiple studies have observed nanostructures in traditionally-manufactured homeopathic medicines. Homeopathy is a 200-year-old system of complementary and alternative medicine used worldwide. The nature of homeopathic medicines has historically stimulated much debate. The present placebo-controlled study extended previous work to characterize nanoparticles (NPs) in homeopathically-prepared Gelsemium sempervirens (GELS), a natural botanical source with previously-documented anxiolytic, analgesic, and anticancer properties. An ethanolic GELS herbal extract was serially diluted and succussed (agitated) in a 95% ethanol-water diluent solvent in glass vials, following Homeopathic Pharmacopoeia of the U.S. guidelines. GELS (VERUM, at homeopathic potencies of 6C, 30C, 200C, each n=3 vials), succussed controls (SUCC-CONT, at homeopathic potencies of 6C, 30C, 200C, each n=3), and one set of unsuccussed solvent control vials also used natural cork (Quercus suber) stoppers (UNSUCC-cork, n=3). A final set of unsuccussed solvent controls used silicone stoppers (UNSUCCsilicone, n=3). Analytical methods included nanoparticle tracking analysis (NTA), zeta potentials, and UV-Visible spectroscopy. NTA revealed >4 x 10 8 nanoparticles per milliliter in all VERUM, SUCC-CONT, and UNSUCC-cork vials, significantly more than the UNSUCC-silicone controls. Particle sizes were polydisperse, significantly larger in the VERUM 30C at 129.8 nanometers versus SUCC-CONT at 6C, 30C, 200C and the UNSUCC-cork controls. Zeta potentials consistent with greater particle stability were significantly most negative in the VERUM GELS 200C (-47.75 mV). Within the UV-vis wavelength range 300-400 nm, the SUCC-CONT 30C exhibited significantly higher, whereas UNSUCC-silicone stopper controls had significantly lower, mean absorbance than all other samples. Taken together, the data suggest that traditional homeopathic methods involving succussions release not only the previously-shown silica from glassware walls, but also Quercus suber materials from natural cork stoppers to stabilize NPs in solution. With verum source material Gelsemium, additional NP size growth and surface stabilization can occur. Further study of homeopathic manufacturing materials and methods and their biological correlates is indicated.