The polyphenol complex of cotton leaves, expressing an abnormal red coloration under abiotic stress, was analysed by using high performance liquid chromatography (HPLQ. Different polyphenol types - cinnamic acid derivatives (C-6-C-3), flavonoids (C-6-C-3-C-6) and anthocyanins (C-6-C-3-C-6(+)) were separated. It was shown that reddening of cotton leaves was related to an increased formation of anthocyanin pigments, mainly cyanidin glycosides, while cinnamic acid derivatives and flavonoids were not significantly changed. The plausible protective role of anthocyanins is discussed, particularly taking into account the shift from malvidin to cyanidin aglycones, i.e. to o-dihydroxy substitution in the B-ring of the anthocyanins during cotton leaf reddening that may determine a higher antioxidant and antiradical capacity.