what can a person do if while in the hospital they are given medication they are allergic to?

It would depend on what kind of damages you had as a result to the allergic medication.  Did you take the medication?  Did you have a reaction? Did the doctor/hospital know you were allergic to this medication?  Did you know you were allergic to this medication?  More information is needed.  But, generally, you would have to have had some type of reaction which resulted in monetary damages and it would have to be determined whether the doctor/nurse/health care provider's act in giving you the allergic medication fell below the standard of care.  That will depend on the facts of your potential case along with state law.  In addition, medical malpractice cases usually require the hiring of an expert witness.  If  you believe that you have a viable case, I recommend getting your medical records related to this and then calling attorneys to see if you can get a free consultation.  Best of luck. NOTE:  This response is general in nature and should not be considered legal advice.  No attorney-client relation exists or is formed by this response.