A standardized plant composition--UP446, with primarily baicalin from the roots of Scutellaria baicalensis and (+)-catechin from the heartwoods of Acacia catechu--has been used in both joint supplements and a prescription medical food. The in vitro and in vivo safety evaluations of UP446 have been reported previously. A supplemental 90-day oral toxicity study was conducted in Hsd:SD(R) rats to determine the potential of UP446 to produce toxicity. Four groups (10 males and 10 females per group) of dose levels of 250, 500, and 1000 mg/kg/day of the test article, as well as a control (0.5% carboxymethylcellulose) were tested. There were no test article related mortalities or ophthalmological, neurological (Functional Observational Battery and motor activity), body weight, feed consumption, clinical observation, organ weight changes, gross finding, clinical or histopathological alterations. Normal sperm count and comparable estrus staging were observed. A dose of 1000 mg/kg/day was identified as the NOAEL (no-observed-adverse-effect-level) in this study.