Stings from the hydrozoan species in the genus Physalia cause intense, immediate skin pain and elicit serious systemic effects. There has been much scientific debate about the most appropriate first aid for these stings, particularly with regard to whether vinegar use is appropriate (most current recommendations recommend against vinegar).

However, even slight dilution of vinegar reduced its protective effects. Alcohols and folk remedies, such as urine, baking soda and shaving cream, caused varying amounts of immediate cnidae discharge and failed to inhibit further discharge, and thus likely worsen stings.

Wilcox C, Headlam J, Doyle T, Yanagihara A. Assessing the efficacy of first-aid measures in Physalia sp. envenomation, using solution-and blood agarose-based models. Toxins. 2017;9(5):149.