If someone is allergic to amoxicillin, would it be safe to take penicillin?

No: Many people have cross allergenicty to penicillin and amoxicillin. Assuming you have a true allergy to one of these, it is best to avoid the other. Talk to your physician about an alternate drug.

Absolutely not!!!!: These two drugs are essentially one and the same from an allergic standpoint. If you are truly allergic (some people are not sure) the risks of taking penicillin can be life-threatening.

Safer to avoid: Typically patients who are allergic to Amoxicillin are also allergic to penicillin, however you can be allergic to Amoxicillin alone. You would need an allergy evaluation to determine the best course of action. Skin testing with prepen and oral challenge to antibiotics in an allergist's office should be considered depending upon the initial reaction to amoxicillin.