It was hypothesised that reintroduction of Australian native mammals, currently being severely impacted by feral cat predation, would be more successful if these mammals could have a retained toxicity as discussed in historical accounts. Seeds from the Australian genus Gastrolobium (Fabaceae: Mirbelieae) were analysed in the search for a toxicant that would explain historical accounts of toxic wildlife. Numerous accounts referring to bronzewing pigeons having toxic bones were specifically noted. Analysis of this seed found no evidence for rapidly toxic alkaloids previously reported as being extracted from the leaves of York Road poison and box poison. However, evidence for the presence of organo-fluorine compounds in addition to the reported fluoroacetate (Compound 1080) was discovered. A limited cat dosing trial found that a highly fluorinated box poison seed caused a cat to cease respiration in 82 minutes, but its chloroform extract produced no adverse physiological response. In addition, citrate accumulation appeared more rapid and acute with increasing seed ‘total fluorine.’