Many schemes have what they call a medical savings account or MSA. This is usually a percentage of your monthly contribution (to a maximum of 25%) , which is made available for payment of day-to-day medical expenses. Certain sub-limits still apply. If your MSA becomes exhausted, you will be liable for day-to-day medical expenses.
Chronic medication and hospitalisation costs are not paid out of your MSA. Money that is not used, is usually carried over to the next year. Should you resign from the scheme, any money left over in the MSA will be paid out to you.