Thanks to rare case from the past, doctor identifies the reason a patient's blood was blue WMUR ManchesterA woman used a numbing agent to treat a toothache. The next day her blood turned blue The Mercury NewsA numbing medicine turned a woman's blood blue CNNRhode Island woman’s blood turned blue after she used numbing cream to treat toothache FOX 31 DenverRhode Island Woman’s Blood Turned Blue by Numbing Medication KTLA Los AngelesView full coverage on Google News