Definition of Reasonable Care
Reasonable Care is the level of care which a reasonable and ordinary person would use under comparable circumstances. If a person does not use reasonable care and the injured party can show they owed them a duty of care, that person can be liable for their negligence if there is injury. Reasonable care applies only to the "ordinary" person so a child or someone with mental limitations would have a lower standard of reasonable care than another person.
In personal injury law reasonable care is the standard to assess liability. If you have a personal injury case for medical malpractice you must prove professional negligence. But the assumption is a doctor's duty of care is different than another "ordinary person." For example, if a patient has been injured due to the actions of a doctor and they can prove the doctor had a duty of care to them and they failed to exercise reasonable care, the doctor may be liable for damages. Duty of care in this particular situation is compared to the manner consistent with other medical professionals in a similar situation.