The following groups should avoid or use numbing creams and liquids with caution: those allergic to any ingredient, individuals with broken skin or severe inflammation, people taking specific medications, those with methemoglobinemia, and infants under 2 years old (benzocaine is especially contraindicated). Pregnant or breastfeeding women, children, the elderly, and individuals with heart, liver, kidney conditions, or skin diseases should only use them under medical supervision.

Many people find anesthetic creams/liquids ineffective ,primarily due to: variations in skin thickness and barrier function affecting absorption; incorrect applicationinsufficient amount, short waiting time, or lack of occlusive dressing to enhance penetration; certain individuals (e.g., some with red-hair gene variants) have innate lower sensitivity, and frequent use may lead to tolerance. It should also be noted that anesthetics mainly relieve surface stinging pain, with limited effect on deep pressure or dull pain, while psychological tension can amplify pain perception.

If anesthetic cream/liquid enters sensitive areas such as the eyes or mouth, immediate action must be taken: Promptly and continuously flush the affected area with plenty of clean water(hold the eyelid open if exposed to the eyes); do not rub the area or induce vomiting; if systemic symptoms such as dizziness, difficulty breathing, or palpitations occur, seek immediate emergency care.