A person who is 16 years of age or older and who is of sound mind has a right to make decisions which affect his or her life and welfare, and to decide what risks he or she is willing to take in receiving medical treatment.
Before a person can properly exercise this right and decide to either consent to or refuse particular medical treatment, he or she needs to have a reasonable understanding of what that treatment involves. As that information can only come from the treating health professional, it is part of their duty to provide a proper explanation of the medical treatment and the risks involved.
Section 15 of the Consent to Medical Treatment and Palliative Care Act 1995 (SA) states that doctors have a duty to explain to patients, so far as may be practicable and reasonable in the circumstances:
The High Court of Australia in Rogers v Whittaker (1992) 175 CLR 479;  HCA 58 has said that a health professional has a duty to warn a patient of a material risk inherent in proposed treatment. A risk is material if in the particular case:
The High Court also agreed with the reasons expressed in an earlier South Australian case F v R (1983) 33 SASR 189, that the amount of information to be provided to the patient depends on the circumstances.
Some circumstances affecting the amount of information to be provided include:
The law recognises that a health professional is justified in withholding information if there are reasonable grounds for believing that the physical or mental health of the patient might be seriously harmed by knowing particular information, or that the patient's temperament or emotional state is such that the patient would be unable to make a rational decision based on that information. It is also recognised that some people simply wish to leave decisions about their medical treatment in the hands of their health professional and that it would be an unnecessary and additional burden on such patients to force health professionals to discuss all details of treatment with them.
Insufficient or wrong information does not amount to negligence unless it can be shown, among other things, that sufficient or correct information would have resulted in a different decision about undergoing the treatment.