Shin'eiyaku

Shineiyaku are pills designed by Kisuke Urahara to help Shinigami who have lost their Bankai to Quincy Medallions. By temporarily causing the user to Hollowfy, it effectively makes the Bankai "poison" for a Quincy due to their inability to take in Hollow reiatsu without their souls being destroyed in the process. The pills are taken by touching them with their hands, feet, or sword. The effects were first seen when Toshiro Hitsugaya's stolen Bankai, Daiguren Hyorinmaru, caused Cang Du to become suddenly injured.