Abstract: Zwitterionic compounds selected from:taurine (2-aminoethanesulphonic acid),2(N-morpholino)ethanesulphonic acid (MES),N-(2-acetamido)iminodiacetic acid (ADA),piperazine-N,N'bis(2-ethanesulphonic acid (PIPES),N-(2-acetamido)-2-aminoethanesulphonic acid (ACES),N,N-bis(2-hydroxyethyl)-2-aminoethanesulphonic acid (BES),3-(N-morpholino)propanesulphonic (MOPS),N-N[tris(hydroxymethyl)-methyl]-2-aminoethanesulphonic acid (TES),N-2-hydroxyethylpiperazine-N'-2-ethanesulphonic acid (HEPES),N-2-hydroxyethylpiperazine-N'3-propanesulphonic acid (H)EPPS),2-(cyclohexylamino)ethanesulphonic acid (CHES) or 3-(cyclohexylamino)propanesulphonic acid (CAPS),and their N-halo derivatives can be used separately or in combination in the treatment of related clinical conditions by stimulating myeloperoxidase activity, which in turn stimulates hypochlorous acid production in vivo, which leads inter alia to enhanced leukotriene inactivation.