In the Commonwealth, there are various doctors who can restore HP, purge radiation, cure addiction, and in many cases also sell medical supplies. In Survival mode, doctors can also cure diseases and heal crippled limbs whenever they heal the Sole Survivor's hit points.
Fees for healing HP are variable depending on the degree of HP lost.
Fees charged by doctors for medical services are not added to their caps available in the barter screen.
Any settler assigned to a clinic also offers these same services, except on the Island, where they will only sell medical supplies.