This opinion considers the safety and efficacy of 17 compounds belonging to chemical group 5 when used as feed flavourings for all animal species. Isopropanol and isopropyl tetradecanoate are safe at a maximum dose level of 25 mg and 5 mg/kg feed, respectively, based on comparable levels of exposure of humans and animals to isopropanol. From toxicological data, heptan-2-one and pentan-2one are safe at the proposed maximum dose level (5 mg/kg) for all species except piglets (4 mg/kg), chickens for fattening and laying hens (3 mg/kg) and cats (2 mg/kg). Since no acceptable toxicological data are available for the remaining compounds, the threshold of toxicological concern approach was used to calculate maximum safe concentrations in feed. For octan-2-ol, pentan-2-ol, octan-3-ol and butan-2-one the safe level is 1.5 mg/kg feed for cattle, salmonids and non-foodproducing animals and 1 mg/kg feed for pigs and poultry. For 6-methylhept-5-en-2-one, undecan-2one, octan-2-one, nonan-2-one, octan-3-one, 6-methylhepta-3,5-dien-2-one, tridecan-2-one, nonan-3one and decan-2-one, the corresponding values are 0.5 mg/kg (cattle, salmonids and non-foodproducing animals) and 0.3 mg/kg (pigs and poultry). Mammals, birds and fish share a similar capacity to metabolise secondary alcohols, ketones and esters to innocuous substances. Consequently, no safety concern would arise for consumers from the use of these compounds as proposed in feeds. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) considers all the compounds under assessment as irritants to skin, eyes and respiratory tract, and as skin sensitisers. Use of the compounds in animal feed at the maximum safe level is considered safe for the environment, except for nonan-3-one in sea cages, where only 0.047 mg/kg is safe. Since all of the compounds are used in food as flavourings and their function in feed is essentially the same as that in food no demonstration of efficacy is necessary. Feed), 2015. Scientific opinion on the safety and efficacy of saturated and unsaturated aliphatic secondary alcohols, ketones and esters with esters containing secondary alcohols belonging chemical group 5 when used as flavourings for all animal species.