mine got ill all by themselves i didn't have to do anything to make it happen just watch the moodlet as my clue was an orange moodlet and if the sim does get ill use a sim computer to order the medicine it'll appear in the sims inventory then use it from the inventory for the sim to get better
when sick can you get your sim to go to the hospital and get diagnosed and treated just like you do in the doctor career except your the patient this time...like when your sim has a baby
There are no way to intentionally get ill. Just play the game and it will eventually happen.
If you download MC Command center you can go into sim cheats and add bthe buff for getting sick there, works most of the time for me
