The disease-preventive and medicinal properties of plant polyphenolic compounds have long been known. As active ingredients, they are used to prevent and treat many noncommunicable
diseases. In recent decades, marine macroalgae have attracted the attention of biotechnologists and
pharmacologists as a promising and almost inexhaustible source of polyphenols. This heterogeneous
group of compounds contains many biopolymers with unique structure and biological properties that
exhibit high anti-infective activity. In the present review, the authors focus on the antiviral potential
of polyphenolic compounds (phlorotannins) from marine algae and consider the mechanisms of their
action as well as other biological properties of these compounds that have effects on the progress
and outcome of viral infections. Effective nutraceuticals, to be potentially developed on the basis
of algal polyphenols, can also be used in the complex therapy of viral diseases. It is necessary to
extend in vivo studies on laboratory animals, which subsequently will allow proceeding to clinical
tests. Polyphenolic compounds have a great potential as active ingredients to be used for the creation
of new antiviral pharmaceutical substances.