“What are the side effects of contrast dye after a CT scan?”

Usually nothing....upon injection, you will likely experience the feeling as if you've wet your pants....it's weird and it's common. Also, upon injection, you may have a metallic taste in your mouth, also common. Immediate side effects can be headache, nausea, and vomiting, and they are not common. Allergy is what we all are wary of. Rash, hives, and other anaphylactic
symptoms and range from minimal to life threatening, but all are very uncommon. CT contrast has also gotten bad press about inducing renal insufficiency. We are learning that this is largely overestimated, but it's something to which we remain alert. All in all, you should be fine.
All the best,