Depends on what it is...if it includes a severe headache, no...if it is something that I know will subside in a matter of time of course hit the gym and work it out of my system.
Yes I do. I look at it two ways. It helps my get better faster and I dont want to pass my illness on to others in the gym that is totally unfair and also I look at it as a couple days of extra healing from the beating I give myself all the time in the gym.