5-Fluorouracil (5-FU) is a uracil analog, an inhibitor of DNA synthesis. 5-Fluorouracil has antitumor activity and affects pyrimidine synthesis through inhibition of thymidylate synthase. 5-Fluorouracil causes apoptosis and autophagy.

CWH22 organoids:3.3 μM, TE-15 cells proliferation:39.81 μM, CLM22 organoids:3.78 μM, KYSE30 cells proliferation:3.89 μM, TE-8 cells proliferation:1 μM, TE-3 cells proliferation:4.37 μM, TE-12 cells proliferation:2.95 μM, KYSE410 cells proliferation:8.51 μM, TE-1 cells proliferation:27.54 μM

After a 7-day habituation period, the mice were divided into three groups (vehicle group, dextrin group, and ED group; n = 6 mice per group) that had the same mean body weight (time of grouping was designated as day 0). Then, mice were treated by tail vein injections from day 0 to 4; mice in the dextrin and ED groups received 40 mg/kg/day of 5- fluorouracil (5-FU) injection 250 mg, while mice in the vehicle group received 10 mL/kg/day physiological saline, which was equivalent to the dose of 5-FU. Additionally, twice a day from day 0 to 6, ED group mice received 1.6 kcal/0.8 mL/day ED administered orally, while mice in the vehicle and dextrin groups received dextrin containing the same amount of calories. Body weight and food consumption were measured before administration of 5-FU and ED on days 0 and 7. Food consumption was measured with respect to each group. Mice were accommodated individually in specially prepared polycarbonate cages, and two or more fresh stools per mouse were scored as follows: 0, the stools were not crushed when pushed by human fingers; 1, the stools were crushed, but the core remained when pushed by human fingers; 2, the stools were crushed and the core did not remain when pushed by human fingers; 3, the stools were crushed and stuck to the fingers when pushed by human fingers; 4, the stools lost their shape just from being touched. Autopsies were conducted on day 7. After bleeding, the large intestine (the colon and rectum) was taken, and the length was measured. The lumen was washed with physiological saline, the excess water was wiped off, and specimens were weighed. Section 3 cm distal from the center of the large intestine was fixed with formalin for histological evaluation. Salivary glands (the submandibular gland and sublingual gland) were collected and weighed. The collected salivary glands were fixed with formalin, and after the tissue sections were prepared, they were stained with hematoxylin and eosin [3].