Which of the following is prohibited in chiropractic advertising?

Deceiving or misleading the public in chiropractic advertising is prohibited because it undermines the integrity of the profession and can compromise patient trust. The chiropractic practice is grounded in honesty, ethical behavior, and the promotion of factual information about services and treatments. Misleading claims can not only misinform potential patients but also lead to legal repercussions for practitioners, as such practices violate regulations set forth by state boards and governing bodies aimed at protecting public health and safety.

Regarding the other options, providing testimonials may have specific regulations governing them, such as requiring that they do not misrepresent services or outcomes. Offering free consultations is generally permissible unless certain conditions tied to patient expectations or other legalities are violated. Discount advertising can also be allowed, provided it does not contain deceptive language or imply unrealistic results. Therefore, while some forms of advertising may come with restrictions, promoting honesty and clarity is what is most crucial in ensuring ethical practice in the chiropractic field.