1. National consumer affairs center of Japan: note! Accidental ingestion of medicine packaging sheet that stands out for elderly people – Swallowed PTP packaging may damage throat and esophagus. https://www.kokusen.go.jp/news/data/n-20100915_1.html (In Japanese) Accessed 7 Apr 2020. (In Japanese).
2. Ministry of health, labor and welfare Japan: prevention of accidental ingestion of PTP packaging sheets. https://www.mhlw.go.jp/stf/shingi/2r9852000001of2m-att/2r9852000001ofoz.pdf Accessed 7 Apr 2020. (In Japanese).
3. Japan gastroenterological endoscopy society post-graduate educational committee: Akamatsu T, Shirai T, Toyonaga T. Guidelines for foreign matter removal. Gastrointestinal endoscopy guidelines 3rd Edition. Tokyo. Igakushoin; 2006. pp. 206–214. (In Japanese).
4. Fujii K, Nitta T, Kawasaki H. A case of sigmoid colon perforation caused by accidental ingestion of a press-through package. J Jpn Colorectol. 2015;68:163–7 (In Japanese with English abstract).
5. Toyoda N, Matsuura N, Tachikake H. The role and clinical background of CT examination in cases of accidental ingestion of press-through package (PTP). J Hiroshima Med Ass. 2016;69:182–7 (In Japanese).