The subacute toxicity of xylooligosaccharide (XO) was evaluated in SD rats. Groups of 60 male and 60 female rats were orally administered with 0, 333, 1000 or 3000 mg/kg of XO for 13 weeks. The changes of body weight, food and water consumption were investigated for 17 weeks, while heamatological values and histopathological findings were investigated at the end of the 13 weeks and 17 weeks including 4 weeks of recovery periods. No death and toxic effects were observed during the test periods. There were statistically significant changes in several parameters, but these change had no direct relationship to dosage. Clinical changes were general occurrence and no specific toxicity was related to XO. Gross necropsy and histopathology revealed that no target organs were found in the treated mouse with XO. According to the results, no-observed effect level of XO is estimated to be above 3000 mg/kg.

To evaluate the bacterial reverse mutation of xylooligosaccharide(XO)s the in vitro Ames test using Salmonella typhimurium (TA98, TA100, TA1535, TA1537) and Escherichia coli (WP2 uvrA) was performed. XO was negative in Ames test with Salmonella typhimurium and Escherichia coli with and without rat liver microsomal enzyme (S-9 fraction). According to the results, XO does not cause bacterial reverse mutation.

The acute toxicity of xylooligosaccharide(XO) was evaluated in SD rats. Groups of 15 male and 15 female rats were orally administered XO (0, 5000 or 10000 ㎎/㎏). The changes of body weight and clinical signs were investigated for 14 days after treatments. No death and toxic effects were observed for 14 days. Soft stool and diarrhea appeared right after treatment for over dose and non-digestive feature of XO but these clinical signs disappeared on the next day. No significant changes in body weight and abnormal gross findings were observed in relation to XO. According to the results, XO has no special toxic effects and LD50 values of XO are above 10000 ㎎/㎏ in male and female rats.