Propanol (P) and dimethylsulphide (DMS) are two of many fermentation products that may be detected in small amounts in silage. When P alone, or together with DMS, was mixed into the silage before feeding, silage intake was slightly reduced but total DM intake was not affected. Both treatments reduced significantly the organoleptic quality of evening milk. This was mainly due to increased frequency of miscellaneous milk flavour. No significant difference in milk composition or taste was detected between cows fed P or P+DMS, suggesting that the milk taint was caused by propanol.