Use of a 1-(3-chlorophenyl)-3-alkylpiperazine of formula (I), in racemic (R,S) form or in the form of the (S) enantiomer, in which R is a linear or branched alkyl group having from 1 to 3 carbon atoms, or of an addition salt thereof with a pharmaceutically acceptable organic or inorganic acid, for treating appetite disorder. A pharmaceutical composition that comprises a therapeutically effective amount of a 1-(3-chlorophenyl)-3-alkylpiperazine of formula (I) as previously defined or of an addition salt thereof with a pharmaceutically acceptable organic or inorganic acid, and at least one pharmaceutically acceptable excipient.