A compound constituting C20- N -acyl derivative of salinomycin, the compound having the general formula:, wherein: - X denotes R, O-R or NH-R; - R denotes: - a straight-chain or branched-chain alkyl group comprising 1 to 10 carbons, - a straight-chain or branched-chain alkyl group comprising 1 to 10 carbons which is substituted at any position of the carbon chain by 1 to 5 halogens, which may be present at the same carbon or at different carbons, - a straight-chain alkyl group comprising 2 to 10 carbons which comprises ether moiety at any position of the carbon chain, - a straight-chain alkyl group comprising 3 to 10 carbons which comprises multiple bonds, either double or triple bonds, at any position of the carbon chain, - a monocyclic, dicyclic or tricyclic alkyl group comprising 5 to 10 carbons, - an aromatic aryl group, wherein those comprising a six-membered aromatic ring are preferred, - an aromatic aryl group substituted by 1 to 3 substituents independently selected from alkyl, alkoxy, hydroxy, nitro and nitrile groups or halogens, - an aromatic heteroaryl group, wherein 1 or more carbons are substituted by 1 or more heteroatoms from a group comprising atoms of oxygen, nitrogen or sulphur, or - an alkyl-aryl group, wherein the aromatic aryl group as defined above is linked to a salinomycin molecule by a carbon chain comprising 1 to 5 carbons (alkyl comprising 1-5 carbons); or a salt thereof. - X denotes R, O-R or NH-R; - R denotes: - a straight-chain or branched-chain alkyl group comprising 1 to 10 carbons, - a straight-chain or branched-chain alkyl group comprising 1 to 10 carbons which is substituted at any position of the carbon chain by 1 to 5 halogens, which may be present at the same carbon or at different carbons, - a straight-chain alkyl group comprising 2 to 10 carbons which comprises ether moiety at any position of the carbon chain, - a straight-chain alkyl group comprising 3 to 10 carbons which comprises multiple bonds, either double or triple bonds, at any position of the carbon chain, - a monocyclic, dicyclic or tricyclic alkyl group comprising 5 to 10 carbons, - an aromatic aryl group, wherein those comprising a six-membered aromatic ring are preferred, - an aromatic aryl group substituted by 1 to 3 substituents independently selected from alkyl, alkoxy, hydroxy, nitro and nitrile groups or halogens, - an aromatic heteroaryl group, wherein 1 or more carbons are substituted by 1 or more heteroatoms from a group comprising atoms of oxygen, nitrogen or sulphur, or - an alkyl-aryl group, wherein the aromatic aryl group as defined above is linked to a salinomycin molecule by a carbon chain comprising 1 to 5 carbons (alkyl comprising 1-5 carbons); - R denotes: - a straight-chain or branched-chain alkyl group comprising 1 to 10 carbons, - a straight-chain or branched-chain alkyl group comprising 1 to 10 carbons which is substituted at any position of the carbon chain by 1 to 5 halogens, which may be present at the same carbon or at different carbons, - a straight-chain alkyl group comprising 2 to 10 carbons which comprises ether moiety at any position of the carbon chain, - a straight-chain alkyl group comprising 3 to 10 carbons which comprises multiple bonds, either double or triple bonds, at any position of the carbon chain, - a monocyclic, dicyclic or tricyclic alkyl group comprising 5 to 10 carbons, - an aromatic aryl group, wherein those comprising a six-membered aromatic ring are preferred, - an aromatic aryl group substituted by 1 to 3 substituents independently selected from alkyl, alkoxy, hydroxy, nitro and nitrile groups or halogens, - an aromatic heteroaryl group, wherein 1 or more carbons are substituted by 1 or more heteroatoms from a group comprising atoms of oxygen, nitrogen or sulphur, or - an alkyl-aryl group, wherein the aromatic aryl group as defined above is linked to a salinomycin molecule by a carbon chain comprising 1 to 5 carbons (alkyl comprising 1-5 carbons); - a straight-chain or branched-chain alkyl group comprising 1 to 10 carbons, - a straight-chain or branched-chain alkyl group comprising 1 to 10 carbons which is substituted at any position of the carbon chain by 1 to 5 halogens, which may be present at the same carbon or at different carbons, - a straight-chain alkyl group comprising 2 to 10 carbons which comprises ether moiety at any position of the carbon chain, - a straight-chain alkyl group comprising 3 to 10 carbons which comprises multiple bonds, either double or triple bonds, at any position of the carbon chain, - a monocyclic, dicyclic or tricyclic alkyl group comprising 5 to 10 carbons, - an aromatic aryl group, wherein those comprising a six-membered aromatic ring are preferred, - an aromatic aryl group substituted by 1 to 3 substituents independently selected from alkyl, alkoxy, hydroxy, nitro and nitrile groups or halogens, - an aromatic heteroaryl group, wherein 1 or more carbons are substituted by 1 or more heteroatoms from a group comprising atoms of oxygen, nitrogen or sulphur, or - an alkyl-aryl group, wherein the aromatic aryl group as defined above is linked to a salinomycin molecule by a carbon chain comprising 1 to 5 carbons (alkyl comprising 1-5 carbons);