The present invention relates to deacidification of glyceride oils. The present invention provides a process for removing free fatty acids from glyceride oil, preferably palm oil, containing free fatty acids, said process comprising the steps of: (i) contacting the glyceride oil containing free fatty acids with the basic ionic liquid; wherein the basic ionic liquid has a basic anion selected from hydroxide, alkoxide, alkylcarbonate, hydrogen carbonate, serinate, prolinate, histidinate, threoninate, valinate, asparaginate, taurinate and lysinate; and a cation selected from: [N(R a )(R b )(R c )(R d )] + , wherein: R a , R b , R c and R d are each independently selected from hydrogen, a C 1 to C 8 , straight chain or branched alkyl group or a C 3 to C 6 cycloalkyl group, wherein said alkyl or cycloalkyl groups are unsubstituted or may be substituted by one to three groups selected from: C 1 to C 4 alkoxy, C 2 to C 8 alkoxyalkoxy, C 3 to C 6 cycloalkyl, -OH, -SH, - CO 2 (C 1 to C 6 )alkyl, -OC(O)(C 1 to C 6 )alkyl, or any two of R a , R b , R c and R d combine to form an alkylene chain -(CH 2 ) q - wherein q is from 3 to 6; and (ii) obtaining a treated glyceride oil having a reduced content of free fatty acid compared to the glyceride oil feed of step (i).