Bacteria, plants, fungi, and animals have evolved venoms and toxins over millions of years as a form of defence or as a weapon. Many of these venoms induce rapid tissue necrosis, and the precise molecular mechanisms involved are largely unknown. Since venoms need to interact with our proteins to cause necrosis, we reasoned that diverse venoms may use overlapping strategies to cause us damage. Indeed, by profiling mechanisms of action for multiple unrelated venoms we found some overlap in mechansims used. In one instance, it was determined that venom from a jellyfish (sea nettle) and snake (spitting cobra) seem to use a similar pathway to cause tissue damage. Using our whole-genome CRISPR screening results for how these venoms work we could predict new drugs that could act as venom antidotes. For one of these drugs, a stable and safe WHO essential medication, we observed broad antivenom activity both in vitro and in vivo. Envenomation events, particularly from snakebite, affect millions of people annually resulting in significant morbidity and mortality. Our screening system can be used to further categorise diverse toxins and venoms and pinpoint convergent mechanisms of action. It is hoped we can then use this knowledge to help treat patients exposed to venoms, many of whom live in rural areas within developing countries with few other treatment options available.