Chemical group 9 consists of primary aliphatic saturated or unsaturated alcohols/aldehydes/acids/acetals/esters with a second primary, secondary or tertiary oxygenated functional group including aliphatic lactones, of which 30 are currently authorised for use as flavours in food. The FEEDAP Panel was unable to perform an assessment of 2-oxopropanal because of issues related to the purity of the compound. The FEEDAP Panel concludes that lactic acid, succinic acid, fumaric acid, 4-oxovaleric acid, ethyl lactate, butyl lactate, butyl-O-butyryllactate, hex-3-enyl lactate, hexyl lactate, ethyl acetoacetate, ethyl 4-oxovalerate, diethylsuccinate and diethyl malonate are considered to be safe for all animal species at the use levels proposed when used as feed flavourings; octano-1, 4-lactone, nonano-1, 4-lactone, decano-1, 4-lactone and undecano-1, 4-lactone are safe at 20 mg/kg complete feed; butyro-1, 4-lactone, pentano-1, 4-lactone, hexano-1, 4-lactone, heptano-1, 4-lactone, octano-1, 5-lactone, nonano-1, 5-lactone, decano-1, 5-lactone and undecano-1, 5-lactone at 5 mg/kg complete feed; dodecano-1, 4-lactone, dodecano-1, 5-lactone, tetradecano-1, 5-lactone, and pentadecano-1, 15-lactone at a maximum of 1.5 mg/kg complete feed for cattle, salmonids and non food producing animals and of 1 mg/kg complete feed for pigs and poultry. No safety concern was identified for the consumer from the use of compounds belonging to CG 9 up to the highest safe level in feedingstuffs for all animal species. All compounds should be considered as irritants to skin, eyes and respiratory tract, and as skin sensitizers. The compounds do not pose a risk to the environment when used at concentrations considered safe for the target species. Since all compounds are used in food as flavourings, no further demonstration of efficacy is necessary.