Most platyhelminths are hermaphroditic , meaning that they have both sexes in the one individual.
Unlike other hermaphrodites like earthworms and snails, flatworms perform self-fertilisation, an advantage when you may be the only flatworm in an animal. Platyhelminths feed by absorbing nutrients across their cuticles or skins - they usually have no digestive tract to speak of. Flatworms have completely different metabolisms to nematodes, so common, over the counter worming tablets directed against nematodes like threadworm will have no effect against these worms, and treatment frequently requires prescription medication. The flukes have flat, leaf-shaped, unsegmented bodies. Flukes have complex life-cycles, usually involving two or more intermediate hosts.