Abstract: Novel combinations of an antiprotozoal naphthoquinone and a 4-pyridinol or an alkanoic ester thereof wherein the antiprotozoal activity of the combination is potentiated with respect to the corresponding activity of the components of the combination. The combinations are especially useful for the treatment or porphylaxis of malaria.

Abstract: Pharmaceutical formulations and their preparation, suitable for use in the treatment or prophylaxis of malaria, which comprise a compound of formula (I) ##STR1## where X is hydrogen, an alkali metal, the ammonium radical, or H.(CH.sub.2).sub.n.CO- where n is 0 to 3, together with a compound of formula (II) ##STR2## where R.sup.3 is C1-C5 alkyl and R.sup.6 and R.sup.7 are the same or different and are each selected from alkyl, alkoxy, aralkoxy and di(C1-C5 alkyl) amino. Formulae (I) and (II) include pharmaceutically and pharmacologically acceptable acid addition salts of the respective compounds. Also provided is a method for the treatment of prophylaxis of malaria in a mammal comprising the administration to the mammal in combination of a compound of formula (I) and a compound of formula (II) as above defined.