Osteoporosis (OSP) decreases bone mass and affects millions of people; the diagnosis is often late. Considering the side effects of conventional treatments, search for natural therapies should be a constant. Among natural treatments, herbal medicines stand out with very promising results. One of the plants that has drawn a lot of attention to prevent OSP is Plinia cauliflora (PC) Kausel. The objective was to evaluate the effect of PC extract in the OSP prevention in ovariectomized rats. In total, 60 female Wistar rats were divided into six experimental groups: positive control, negative control, sham, and three groups to test different doses (37.5, 75, and 150 mg) of PC bark extract. Bone mineral density (BMD), bone mineral content (BMC), hormone dosage, and osteocalcin were evaluated. One of the regions evaluated was the legs, where prolonged treatment with extract of PC in 75 mg, had a gain of 1.4 times of BMC. The levels of osteocalcin were found to be high at the lowest dose (37.5 mg), increasing the BMC by 70%, and moderately increasing the levels of dehydroepiandrosterone, proving that the pathway that increases BMC is through osteocalcin. PC resulted in increased BMC related mainly to increased osteocalcin, at the lowest dose preserving the bone matrix.