What should be avoided in hair care when a client has an allergy to certain ingredients?

When a client has an allergy to certain ingredients, it is crucial to avoid applying products without checking the list of ingredients. This practice is essential because even small amounts of an allergenic substance can trigger a reaction in sensitive individuals. By carefully reviewing ingredient lists, barbers can ensure that the products used do not contain allergens that could harm the client. This proactive approach safeguards the client's health and well-being during hair care treatments.

Other options may include using natural products, unscented products, or products labeled for sensitive skin, all of which can be beneficial but do not specifically address the fundamental need to verify ingredient safety in relation to an allergy. The priority should always be to check ingredient lists to prevent any adverse reactions, making this practice a key part of responsible and safe hair care.