Abstract: Compounds of formula (I): ##STR1## or a salt or acyl derivative thereof; whereinY is either --CH.dbd.N or ##STR2## R.sup.1 is hydroxy, halogen, (C.sub.1-4) alkyl, or (C.sub.1-4)alkoxy, R.sup.2 is a nitrogen-containing, basic substituent,R.sup.3 is hydrogen, hydroxy, halogen, (C.sub.1-4) alkyl, (C.sub.1-4) alkoxy or a nitrogen-containing, basic substituent, andR.sup.4 is hydrogen or hydroxy,are useful in treating diarrhoea and scours.

Abstract: A compound of formula (I): ##STR1## or a salt thereof wherein R.sup.1 is halogen, C.sub.1-4 alkyl or C.sub.1-4 alkoxyR.sup.2 is hydrogen, halogen, C.sub.1-4 alkyl or C.sub.1-4 alkoxyR.sup.3 and R.sup.4 are the same or different and each is hydrogen, C.sub.1-4 alkyl or acyl andR.sup.5 is either (i) ##STR2## wherein R.sup.6, R.sup.7 and R.sup.8 are the same or different and each is selected from hydrogen, halogen, alkyl, alkoxy, hydroxy, hydroxyalkyl, alkoxyalkyl, mercapto, mercaptoalkyl, amino, aminoalkyl, nitro, cyano, carboxy or a salt, ester or amide of carboxy provided that at least one of R.sup.6, R.sup.7 and R.sup.8 is other than hydrogen or (ii) ##STR3## wherein R.sup.9, R.sup.10 and R.sup.11 are the same or different and each is selected from hydrogen, halogen, alkyl, alkoxy, hydroxy, hydroxyalkyl, alkoxyalkyl, mercapto, mercaptoalkyl, amino, aminoalkyl, nitro, cyano, carboxy or a salt, ester or amide of carboxyand X is --CH.sub.2 -- or --CH.dbd.CH-- or (iii) ##STR4## wherein R.sup.12 and R.sup.

Abstract: Compounds of formula (I): ##STR1## wherein R.sup.1 and R.sup.2 are the same or different and each is selected from halogen, alkyl, haloalkyl, alkoxy and alkoxyalkyl,R.sup.3, R.sup.4 and R.sup.5 are the same or different and each is alkyl;n is 0,1,2 or 3; andZ is a pharmaceutically or veterinarily acceptable anion, protect animals from death due to enteropathogenic E. coli infection of the gastro-intestinal tract.