Med-pay is a separate coverage on most auto insurance policies, typically with a limit of $1,000 to $10,000. It pays medical bills incurred after a covered accident, whether you were at fault or not. There is no deductible, no premium increase for using it, and no subrogation against you in most situations.
Med-pay is the cleanest source of immediate medical-bill payment after a crash. It pays as bills come in, rather than waiting for a settlement at the end. The at-fault driver's bodily injury coverage reimburses other costs through the settlement, but med-pay is what bridges the gap.
In Missouri and Illinois, med-pay is optional and not usually stacked across multiple vehicles. Pull your declarations page after a crash to confirm your med-pay limit.