After having a mass removed from the colon area why must you be quarantine for three days after chemotherapy and why must you throw away everything?

Chemotherapy: Chemotherapy is often not only damaging to cancer cells, but also to non-cancerous cells. Additionally, the therapy affects cells that divide rapidly. This unfortunately includes immune cells, so while undergoing chemotherapy you are considered to have a compromised immune system. As a result, the precautions you listed protect you from potential infections.

Chemo: You must not be exposed to anything that may make you ill while your immune system is poor due to your treatment.