The invention relates to the use of compounds of the general formula (I) ##STR1## wherein R.sup.1 represents a hydrogen atom or a C.sub.1-10 alkyl, C.sub.3-7 cycloalkyl, C.sub.3-7 cycloalkyl-(C.sub.1-4) alkyl, C.sub.3-6 alkenyl, C.sub.3-10 alkynyl, phenyl or phenyl-C.sub.1-3 alkyl group; and one of the groups represented byR.sup.2, R.sup.3 and R.sup.4 is a hydrogen atom or a C.sub.1-6 alkyl, C.sub.3-7 cycloalkyl, C.sub.2-6 alkenyl or phenyl-C.sub.1-3 alkyl group and each of the other two groups, which may be the same or different, represents a hydrogen atom or a C.sub.1-6 alkyl group;and physiologically acceptable salts and solvates thereof, for the relief of nausea and vomiting and/or the promotion of gastric emptying and for the manufacture of a medicament for this purpose. Promotion of gastric emptying may be for the relief of gastro-intestinal disorders associated with gastric stasis or may be of advantage in radiological examination procedures.