A 28-day dietary study was conducted in Hsd:SD rats to evaluate the safety of PureLo, a non-caloric powdered concentrate of the Chinese fruit Luo Han Guo, which derives its sweetening properties from triterpene glycosides called mogrosides. Groups of 20 rats (10/sex/group) were fed diets containing 0, 10,000, 30,000, or 100,000 ppm PureLo for 28 days (OECD, Redbook 2000). PureLo was well tolerated and produced no significant adverse effects. Reduced body weight and body weight gain in high-dose animals of both sexes were related to sporadic reductions in food consumption; there were no overall differences in feed efficiency. Statistically significant changes in clinical chemistry (decreased bilirubin, increased total protein) and relative organ weights of liver, adrenals, ovaries and/or testes, and epididymides were not correlated with any histopathological findings and were not considered adverse. Although a few clinical and pathological findings suggest possible treatment-related effects, particularly in the high-dose group, these findings were transient, not dose-dependent, non-adverse, inconsistent, occurred only in one sex, and/or not supported by histopathological findings. Under the conditions of this study and based on the toxicological endpoints evaluated, the NOAEL for PureLo was 100,000 ppm in the diet, the highest level tested, equivalent to 7.07 and 7.48 g/kg bw/day for male and female rats, respectively.