Gomphocarpus fruticosus (syn. Asclepias fruticosa) is a species of milkweed native to South Africa. It is also common in New Zealand where it is the main host of the Monarch butterfly. The plant's tissues contain sufficient cardenolides that consumption of significant quantities of the plant's leaves, stems, or fruit may lead to death in livestock and humans. The species is closely related to Gomphocarpus physocarpus.