If your illness is legitimate and you feel as though it has caused disruption to your schooling and adversely affected your results then I don't see why you shouldn't apply - that's what the EAS system is here for.
Hypothetically if someone were to fake an illness with insufficient documentation of details they would not be penalised, they would just be put in the normal pool of applicants or not get any bonus points. However, if this happened for someone trying to get into medicine it might be brought up in an interview where it might be hard for them to defend themselves.