https://acmt.net/ACMT_Code_of_Ethics.html
American College of Medical Toxicology Code of Ethics for Medical Toxicologists
Expert Testimony
It is recognized that the discipline of medical toxicology has a unique relationship with judicial matters. This is because medical toxicologists specialize in being knowledgeable about the capacity of chemical substances to do harm. Because of their unique knowledge base the provision of legal testimony is considered to be a component of the practice of medical toxicology.
It is important the medical toxicologist consistently bear in mind the purpose of an expert witness within the legal system. The expert is not present as an advocate nor are they present to adjudicate the matter at hand. Rather, he/she is present exclusively to assist the trier of fact via the presentation of factual knowledge and scientifically-based opinion and the conveyance of understanding regarding the matter under consideration. All testimony must be objective and impartial.
Compensation of the expert should be reasonable and commensurate with the time and effort invested by the expert as well as their experience, unique expertise, and ability. An expert should not, under any circumstances, link compensation of any kind to the outcome of the case.
The physician expert witness should, in general, not make such activities the sole focus of their professional practice.
Consideration can, however, be given to special circumstances such as retirement from or temporary interruption of clinical practice, so long as the expert can demonstrate that these circumstances do not materially diminish the expert’s competency to address the issues at hand.