Dietary administration of α-terpineol to Sprague-Dawley rats for 90 days.

α-Terpineol is a flavoring ingredient that occurs naturally in spices and foods. It has been evaluated by regulatory and scientific expert bodies such as the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 1999 and the European Food Safety Authority (EFSA) in 2006 and has been determined safe under the conditions of intended use. To ensure the continued safety of high-usage flavoring ingredients, a 90-day Organization for Economic Co-operation and Development (OECD) 408 and Good Laboratory Practice (GLP) compliant study was conducted in Sprague-Dawley (SD) rats (10/sex/groups) at target dietary intakes to achieve doses of 0, 50, 150 or 500 mg/kg bw/day. There were no unscheduled deaths and no adverse changes in ophthalmological examinations, body weight, food consumption, food efficiency, hematology, serum chemistry, urinalysis parameters and macroscopic and microscopic observations. While not statistically significant, excessive fragmentation of sperm (head and tail separating) was observed in high-dose males, resulting in reduced or zero sperm mobility. Based on the specific sperm abnormalities observed, the no-observed-adverse-effect level (NOAEL) was determined to be the middle dose, 146 mg/kg bw/day for male SD rats and 500 mg/kg bw/day, the highest dose tested, for female SD rats.