Health Care Consent Act of Ontario: all about liability and consent

In Ontario health care law, silence can be expensive. A clear proof of this is the Health Care Consent Act, 1996, which imposes clear legal duties on healthcare professionals: disclose the right information, assess whether the patient can actually decide, and follow a precise framework when they cannot. When those duties are not met, the legal consequences tend to speak for themselves.

What is required to be disclosed under the Health Care Consent Act of Ontario?

Under Ontario’s Health Care Consent Act (HCCA), informed consent is more than just a signature on a form or any piece of paper. Rather, consent is a structured legal process with defined disclosure requirements that apply across every health care setting in the province.

Under the law, a physician must communicate the following matters to a patient before any treatment can be given:

• the nature of the treatment
• its expected benefits
• material risks and side effects
• alternative courses of action
• the likely consequences of not receiving the treatment at all

The physician must also respond to requests for additional information, and take reasonable steps to confirm the patient understood what was communicated.

Check out this brief video which explains the legal matters on capacity to consent to treatment in Ontario:

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The reasonable person standard

The benchmark for adequate disclosure is objective. The Health Care Consent Act of Ontario requires physicians to provide what a reasonable person in the same circumstances would need to make a treatment decision. This standard operates on two levels:

• it covers information that a broad range of patients would require, and
• it captures the information specific to this particular patient’s situation

What counts as a material risk

Material risks are broader than many practitioners assume. Under Ontario’s Health Care Consent Act, a risk is material if it is:

• probable or likely to occur
• possible but serious in its consequences if it does occur
• something a reasonable person in the same circumstances would want to know before deciding

A risk does not need to be common to require disclosure. This means that low-probability risks with serious consequences are still material.

A signed form does not prove informed consent

While a signed form is evidence that a form was signed, it does not necessarily mean that informed consent was obtained. As such, valid consent requires a genuine dialogue, in which the patient had a real opportunity to ask questions and receive answers. The obligation to obtain consent, which must be valid and informed, always rests with the physician proposing the treatment.

When does a failure of informed consent becomes a medical malpractice liability?

Not every gap in the consent process results in a civil claim. But, when a failure is material and causes identifiable harm, Ontario’s law offers two distinct paths to liability among medical professionals.

Battery vs. Negligence

The legal exposure is battery if a physician administers treatment without any valid consent. Battery is an unauthorized touching that is actionable without proof that the undisclosed risks specifically caused the harm. In other words, the fact of unconsented treatment is enough when it comes to battery.

On the other hand, the claim is more likely to proceed in negligence if consent was obtained but disclosure was inadequate. To succeed, the plaintiff must show that the:

• disclosure fell short of what the HCCA requires
• missing information was material
• non-disclosure caused the harm the patient suffered
• HCCA’s liability shield is conditional

The HCCA protects practitioners who act in good faith and comply with its requirements. However, that protection disappears when a practitioner:

• proceeds with treatment without valid consent,
• relies on a substitute decision maker (SDM) who was not properly identified under the HCCA’s hierarchy, or
• ignores a patient’s prior capable wish to refuse the treatment in question

Documented refusals carry legal force

Under Ontario’s HCCA, a patient who expressed a wish to refuse a particular treatment while capable has effectively refused it in advance. That refusal does not expire when the patient later becomes incapable. That is why the civil exposure is significant if a practitioner administers the treatment disregarding such wish, even in an emergency.

To be sure, advance directives and documented refusals must not be treated as mere administrative paperwork, since they are legally binding instructions under the HCCA, and courts treat them accordingly.

Here’s a video which explains the HCCA of Ontario as applied to midwives in the province, which can be used by lawyers to help explain the law to their clients:

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How do Ontario courts assess causation when a patient would have refused treatment?

Establishing that a physician failed to meet the HCCA’s disclosure requirements is only the first element of a malpractice claim. Proving that the failure caused the patient’s harm is the harder part, and it is where many claims either succeed or fail.

The modified objective test

Ontario courts apply the modified objective test for causation in failure-to-disclose cases. The test originates from the Supreme Court of Canada’s decision in Reibl v. Hughes, [1980] 2 SCR 880, and has been consistently applied in Ontario medical malpractice litigation.

The question the test poses is: what would a reasonable patient in the same circumstances as the plaintiff have decided, had they been properly informed?

This is not a purely subjective inquiry, and the court does not simply accept the plaintiff’s evidence that they would have refused treatment. However, it is not purely objective either, since the court accounts for the plaintiff’s specific circumstances (e.g., age, health status, the nature of the procedure, and what was at stake), then asks what a reasonable person in that same position would have done.

What this means for personal injury lawyers

For a lawyer building a failure-to-disclose claim under Ontario’s Health Care Consent Act:

• testimony may or may not be enough: it is necessary to present the testimony from the plaintiff that they would have refused the treatment, but it is not sufficient on its own
• relationship between risk and causation: the more serious and foreseeable the undisclosed risk is, the stronger the causation argument would become
• other necessary pieces of evidence: evidence of the patient’s values, beliefs, and prior decisions helps establish what a reasonable person in their specific circumstances would have chosen

When reconciled, the HCCA’s disclosure standard and the Reibl causation test share the same analytical framework. Both tells that strong evidence of a material disclosure failure tends to support causation as well.

Can capacity findings by the Consent and Capacity Board be used as evidence in civil proceedings?

Yes. With Consent and Capacity Board (CCB) applications rising sharply across Ontario, this question is becoming more relevant for civil litigators.

What the Consent and Capacity Board is

The CCB is an independent administrative tribunal established under the HCCA. Typically, a CCB panel includes a psychiatrist, a public member, and a lawyer who serves as Chair.

Its decisions are legally binding, unless overturned on appeal to the Ontario Superior Court of Justice. For litigators, this gives CCB findings their evidentiary weight in subsequent civil proceedings.

How CCB findings factor into malpractice claims

Two types of CCB outcomes are particularly relevant to civil litigation:

• When the CCB overturns a finding of incapacity: This indicates that the practitioner’s determination was not supported by the evidence. In a malpractice claim, this outcome can support the argument that the practitioner overrode a capable patient’s right to refuse treatment.
• When the CCB confirms incapacity but finds the SDM non-compliant: If the SDM did not follow the patient’s prior capable wishes, that finding goes directly to whether the substitute consent obtained was lawful under the HCCA.

Burden of proof rests with the practitioner

At a CCB hearing, it is the health care provider who has the burden of proving that their finding meets the legal criteria; it is not the patient. If that burden is not met, the failure is on the official record and is available as evidence in subsequent civil proceedings.

Health Care Consent Act of Ontario: silence is not yes

Ontario’s Health Care Consent Act sets a clear standard for every physician in the province: disclose properly, assess capacity honestly, and follow the Act’s framework when a patient cannot decide for themselves. When practitioners fall short, the resulting civil liability is built from the same clinical notes, CCB records, and consent dialogues that practitioners document every day.

For personal injury lawyers, the law functions as a map of legal obligations. It marks where the disclosure duty began, where it was not met, and how the modified objective test in Reibl connects that failure to the harm the client suffered.

In Ontario health care law, silence about material risks is rarely the end of the story.

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