The present invention provides the use of a topical composition comprising an effective amount of at least one plant extract, together with appropriate topical pharmaceutically or cosmetically acceptable carriers and/or excipients, for avoiding the sting of poisonous organisms that contain cnidocysts. The invention further provides a combination for simultaneous, or sequential administration, of at least one plant extract, and an external source of a cation metal selected from the group consisting of lanthanum, gadolinium, zinc, calcium, sodium, potassium, magnesium, and titanium, compositions comprising said combination, and their use for avoiding the sting of poisonous organisms that contain cnidocysts.