There are many side effects of chemotherapy
. Since there are so many different types of chemo and they each have different side effects they can create, it is not possible for me to tell if your dad's particular chemo regimen has the potential to cause a really bad runny nose. The best type of physician to ask this question to is an oncologist
(likely the doctor
that your dad is seeing for his cancer) Even if a runny nose is not a side effect of the chemo, it still could be related. Most chemotherapeutic agents cause the immune system to not work as well as it should. When the immune system is knocked down, sometimes infections such as the common cold or a sinus infection can occur more easily. This is a possible cause of his runny nose. I suggest you have your dad bring up this issue at his next visit with his oncologist or whoever is administering his chemotherapy. He or she will know whether the type of chemo he is receiving has the potential to cause a really bad runny nose. If this is not one of the side effects, then he may need treated for a sinus infection or a cold, depending on the cause. I hope he feels better.