Vinegar (4-6% acetic acid) inhibits nematocyst discharge of Box jellyfish but does not provide pain relief from the venom already injected.

Although not proven to inhibit nematocyst discharge of all jellyfish causing Irukandji syndrome, its use is considered good first-aid practice.

Vinegar causes nematocyst discharge of some other jellyfish, including Bluebottle and is therefore recommended only for tropical areas where Box jellyfish and Irukandji stings occur.