What must be done before performing any chemical treatment?

Before performing any chemical treatment, conducting a patch test to check for allergies is essential. This step helps to ensure the safety of the client by identifying any potential allergic reactions to the chemicals that will be used. Many clients may have sensitivities or allergies that are not immediately apparent, and a patch test allows for a small amount of the product to be applied to the skin to observe for any adverse reactions prior to the full treatment. By ensuring that the client does not have an allergic reaction, the risk of complications during or after the treatment is significantly reduced, prioritizing the client's health and well-being.

Choosing the cheapest product available or asking for client feedback on products, while potentially relevant, do not address the critical health and safety concerns associated with chemical treatments. Applying the treatment directly without testing is not advisable, as this could lead to serious allergic reactions or skin damage, which could harm the client and result in liability for the professional.