The Classic Comprehensive Handbook of Cat Care: STOMACH WORMS
Stomach worms infect both cats and dogs and occur mainly in the southeastern United States. They frequently cause vomiting and cannot be differentiated from other causes of vomiting without examination of a fecal sample and the aid of a veterinarian. You can prevent infection of your cat by preventing the ingestion of cockroaches, crickets, and beetles, which serve as intermediate hosts for the development of one type of stomach worm (Physaloptera), as well as the ingestion of vomitus from other infected animals, which may carry a worm called Ollulanus tricuspis.
Piperazine salts, pyrantel pamoate, dichlorvos, or fenbendazole is used for treatment.