If a person had a large adult or colony of tapeworms in their gut, they'd have to eat a trainload of chia seeds for several months to kill all traces of them, including the fanged scolex/head embedded in the gut. (lol)
Tapeworms are the toughest-skinned beasts among parasites. Their outer body covering (tegument) is very thick & composed of several membrane layers .
The only method to penetrate & disintegrate their body & head & remove all traces of them from the GI tract (& systemically if they've disseminated/scattered throughout the body) is with a combination of specific parasite meds (Niclosamide, Albendazole, & Praziquantel).