Previous research has shown that undenatured type II collagen is effective in the treatment of arthritis. The present study evaluated the broad-spectrum safety of UC-II by a variety of toxicological assays including acute oral, acute dermal, primary dermal irritation, and primary eye irritation toxicity. In addition, genotoxicity studies such as Ames bacterial reverse mutation assay and mouse lymphoma tests, as well as a dose-dependent 90-day sub-chronic toxicity study were conducted. Safety studies indicated that acute oral LD(50) of UC-II was greater than 5000 mg/kg in female Sprague-Dawley rats. No changes in body weight or adverse effects were observed following necropsy. Acute dermal LD(50) of UC-II was determined to be greater than 2000 mg/kg. Primary skin irritation tests conducted on New Zealand Albino rabbits classified UC-II as slightly irritating. Primary eye irritation tests conducted on rabbits indicated that UC-II was moderately irritating to the eye. UC-II did not induce mutagenicity in the bacterial reverse mutation test in five Salmonella typhimurium strains either with or without metabolic activation. Similarly, UC-II did not induce a mutagenic effect in the gene mutation test in mouse lymphoma cells either with or without metabolic activation. A dose-dependent 90-day sub-chronic toxicity study revealed no pathologically significant changes in selected organ weights individually or as percentages of body or brain weights. No significant changes were observed in hematology and clinical chemistry. Therefore, the results from the current study show a broad-spectrum safety profile of UC-II.