It's Complicated. The short version is, acute care (hospitalization and such) is covered by the government. Chronic care is not covered. Traveling to another location for treatment that isn't available locally effectively isn't covered (Ontario has a joke of a reimbursement system that will give you back maybe 10% of what you spent if you're lucky, not sure about other provinces). Medication is covered only for some segments of the population (now starting to expand to the entire population for certain types of drugs). Dental is now covered for some segments of the population, but not all. Vision care has never been covered, except for the elderly. Prosthetics and assistive devices are mostly not covered (some of the most basic things may be, but not, for instance, powered wheelchairs). And there's some variation from province to province, because health care is a provincial responsibility.

You can be bankrupted by needing to travel for care or needing expensive meds, in other words, but you won't have to pay if you're in a car accident and get taken to the local hospital.