Canada: "Obvious To Try" Test In Canada: How And When Is It Applied?

Last Updated: July 24 2015
Article by Cameron Weir


In Canada, the subject matter of a claim in a patent must not have been obvious having regard to the citable prior art and the common general knowledge.

Over the years, the test for obviousness in Canada has evolved into a step-by-step inquiry that now requires consideration, in at least some instances, of whether an invention was "obvious to try" to a skilled person at the claim date.

Whether an invention claimed in a patent would have been "obvious to try" is an issue that is increasingly considered by Canadian courts in conducting an obviousness analysis. By way of example, of the 12 decisions issued by the Federal Court in 2014 in which obviousness of an invention was at issue, "obvious to try" was considered in 11 of these decisions. This article will address the factors that Canadian courts look to in assessing the issue and consider in what circumstances an "obvious to try" analysis is most relevant.

The Sanofi test and "obvious to try" considerations

The Supreme Court of Canada in Apotex v Sanofi-Synthelabo ("Sanofi"), 2008 SCC 61, outlined the following four-part test which must be considered when assessing whether a claim was obvious:

  1. Identify the notional "person skilled in the art" and the relevant common general knowledge of that person.
  2. Identify the inventive concept of the claim in question or if that cannot readily be done, construe it.
  3. Identify what, if any differences exist between the matter cited as forming part of the "state of the art" and the inventive concept of the claim or the claim as construed.
  4. Viewed without any knowledge of the alleged invention as claimed, do those differences constitute steps which would have been obvious to the person skilled in the art or do they require any degree of invention?

In the context of the fourth factor, the Court in Sanofi accepted that it may be appropriate in some cases to consider an "obvious to try" analysis. For a finding that an invention was "obvious to try", there must be evidence to establish on a balance of probabilities that it was more or less self-evident to try to obtain the invention. The mere possibility that something might turn up is not sufficient.

The Court in Sanofi listed the following non-exhaustive factors to be considered in an "obvious to try" analysis:

  1. Is it more or less self-evident that what is being tried ought to work? Are there a finite number of identifiable predictable solutions known to persons skilled in the art?
  2. What is the extent, nature and amount of effort required to achieve the invention? Are routine trials carried out or is the experimentation prolonged and arduous, such that the trials would not be considered routine?
  3. Is there a motive provided in the prior art to find the solution the patent addresses?

The Court also acknowledged a fourth factor in the "obvious to try" analysis, namely the actual course of conduct culminating in the making of the invention (i.e., the invention history), in so far as it relates to how the skilled person would have acted in light of the prior art.

Subsequent cases have applied the "obvious to try" test and expanded upon the Court's language in Sanofi.

Self-evident threshold

It must be "very plain", or self-evident, from the prior art and common general knowledge that what is being tested "ought to work". Hindsight is to be avoided. An invention may be "obvious to try" if there are a finite number of possible routes that could be used to solve the problem. An invention that can only be reached when a skilled person makes a series of correct decisions is likely not self-evident or "obvious to try".

Level of effort required

The Court is to consider the extent, nature and amount of effort required to achieve the invention, which is related to the actual course of conduct in making the invention or invention history (the "fourth factor" referred to above).

The mere fact that the invention may be achieved through routine testing does not necessarily render an invention "obvious to try". However, an invention may be "obvious to try" if it was obvious to a skilled person to use routine, known tests in a manner that would lead to the invention.

Regarding the actual course of conduct in making the invention, an invention that is reached quickly, easily and relatively inexpensively in light of the prior art and common general knowledge may be "obvious to try". However, if the efforts involved went beyond mere "bench work" and a lot of time, money and effort were required to reach the solution, the invention may not be "obvious to try".


A skilled person may be highly motivated to solve problems in the art. However, Canadian courts have stated that the focus should be on whether there is a "specific motivation" to pursue the invention – i.e. the particular solution taught by the patent. While a high degree of motivation will likely compel a skilled person to pursue experimentation that they view as "predictable" or having a "fair expectation of success", motivation cannot transform a non-obvious invention into an obvious invention. Therefore, courts consider whether a skilled person is motivated enough to view the success of a particular solution as more or less self-evident and a set of experiments to achieve that solution as "obvious to try".

"Obvious to try" is not the same as "worth a try"

It should be noted that the "obvious to try" test is different from the "worth a try" test that has been used from time to time in other jurisdictions, such as in the United Kingdom. Obvious to try appears to be a higher standard. In Canada, a claimed invention will generally not be held obvious merely because it was "worth a try".

When is an "obvious to try" analysis warranted?

The prevalence of "obvious to try" as an issue in many recent Canadian patent decisions is explained in part because many of these decisions relate to pharmaceuticals, an area of inventive activity in which advances are often made by experimentation. In such fields, there are many interrelated variables with which to experiment. Skilled persons are confronted with multiple routes to explore, with little knowledge about the success of each route. Such development work is relevant to an "obvious to try" analysis, where it would be appropriate to consider, from the standpoint of a skilled person, whether a particular approach would have been self-evident.

The Supreme Court of Canada has specifically stated that pharmaceutical inventions may warrant an "obvious to try" analysis. However, the Federal Court of Appeal has noted that the "obvious to try" approach should not be restricted to pharmaceutical inventions; instead, the applicability of an "obvious to try" analysis is dependent on the facts and evidence in each case.


It is important to note that whether or not a particular experiment was "obvious to try" comprises only one factor to assist in the obviousness inquiry. The overarching question when assessing obviousness is whether the claimed invention is obvious in light of the prior art and common general knowledge.

For further information, please contact a member of our firm's Patents group.

The preceding is intended as a timely update on Canadian intellectual property and technology law. The content is informational only and does not constitute legal or professional advice. To obtain such advice, please communicate with our offices directly.

To print this article, all you need is to be registered on

Click to Login as an existing user or Register so you can print this article.

Cameron Weir
In association with
Related Video
Up-coming Events Search
Font Size:
Mondaq on Twitter
Register for Access and our Free Biweekly Alert for
This service is completely free. Access 250,000 archived articles from 100+ countries and get a personalised email twice a week covering developments (and yes, our lawyers like to think you’ve read our Disclaimer).
Email Address
Company Name
Confirm Password
Mondaq Topics -- Select your Interests
 Law Performance
 Law Practice
 Media & IT
 Real Estate
 Wealth Mgt
Asia Pacific
European Union
Latin America
Middle East
United States
Worldwide Updates
Check to state you have read and
agree to our Terms and Conditions

Terms & Conditions and Privacy Statement (the Website) is owned and managed by Mondaq Ltd and as a user you are granted a non-exclusive, revocable license to access the Website under its terms and conditions of use. Your use of the Website constitutes your agreement to the following terms and conditions of use. Mondaq Ltd may terminate your use of the Website if you are in breach of these terms and conditions or if Mondaq Ltd decides to terminate your license of use for whatever reason.

Use of

You may use the Website but are required to register as a user if you wish to read the full text of the content and articles available (the Content). You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these terms & conditions or with the prior written consent of Mondaq Ltd. You may not use electronic or other means to extract details or information about’s content, users or contributors in order to offer them any services or products which compete directly or indirectly with Mondaq Ltd’s services and products.


Mondaq Ltd and/or its respective suppliers make no representations about the suitability of the information contained in the documents and related graphics published on this server for any purpose. All such documents and related graphics are provided "as is" without warranty of any kind. Mondaq Ltd and/or its respective suppliers hereby disclaim all warranties and conditions with regard to this information, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. In no event shall Mondaq Ltd and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use or performance of information available from this server.

The documents and related graphics published on this server could include technical inaccuracies or typographical errors. Changes are periodically added to the information herein. Mondaq Ltd and/or its respective suppliers may make improvements and/or changes in the product(s) and/or the program(s) described herein at any time.


Mondaq Ltd requires you to register and provide information that personally identifies you, including what sort of information you are interested in, for three primary purposes:

  • To allow you to personalize the Mondaq websites you are visiting.
  • To enable features such as password reminder, newsletter alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our information providers who provide information free for your use.

Mondaq (and its affiliate sites) do not sell or provide your details to third parties other than information providers. The reason we provide our information providers with this information is so that they can measure the response their articles are receiving and provide you with information about their products and services.

If you do not want us to provide your name and email address you may opt out by clicking here .

If you do not wish to receive any future announcements of products and services offered by Mondaq by clicking here .

Information Collection and Use

We require site users to register with Mondaq (and its affiliate sites) to view the free information on the site. We also collect information from our users at several different points on the websites: this is so that we can customise the sites according to individual usage, provide 'session-aware' functionality, and ensure that content is acquired and developed appropriately. This gives us an overall picture of our user profiles, which in turn shows to our Editorial Contributors the type of person they are reaching by posting articles on Mondaq (and its affiliate sites) – meaning more free content for registered users.

We are only able to provide the material on the Mondaq (and its affiliate sites) site free to site visitors because we can pass on information about the pages that users are viewing and the personal information users provide to us (e.g. email addresses) to reputable contributing firms such as law firms who author those pages. We do not sell or rent information to anyone else other than the authors of those pages, who may change from time to time. Should you wish us not to disclose your details to any of these parties, please tick the box above or tick the box marked "Opt out of Registration Information Disclosure" on the Your Profile page. We and our author organisations may only contact you via email or other means if you allow us to do so. Users can opt out of contact when they register on the site, or send an email to with “no disclosure” in the subject heading

Mondaq News Alerts

In order to receive Mondaq News Alerts, users have to complete a separate registration form. This is a personalised service where users choose regions and topics of interest and we send it only to those users who have requested it. Users can stop receiving these Alerts by going to the Mondaq News Alerts page and deselecting all interest areas. In the same way users can amend their personal preferences to add or remove subject areas.


A cookie is a small text file written to a user’s hard drive that contains an identifying user number. The cookies do not contain any personal information about users. We use the cookie so users do not have to log in every time they use the service and the cookie will automatically expire if you do not visit the Mondaq website (or its affiliate sites) for 12 months. We also use the cookie to personalise a user's experience of the site (for example to show information specific to a user's region). As the Mondaq sites are fully personalised and cookies are essential to its core technology the site will function unpredictably with browsers that do not support cookies - or where cookies are disabled (in these circumstances we advise you to attempt to locate the information you require elsewhere on the web). However if you are concerned about the presence of a Mondaq cookie on your machine you can also choose to expire the cookie immediately (remove it) by selecting the 'Log Off' menu option as the last thing you do when you use the site.

Some of our business partners may use cookies on our site (for example, advertisers). However, we have no access to or control over these cookies and we are not aware of any at present that do so.

Log Files

We use IP addresses to analyse trends, administer the site, track movement, and gather broad demographic information for aggregate use. IP addresses are not linked to personally identifiable information.


This web site contains links to other sites. Please be aware that Mondaq (or its affiliate sites) are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of these third party sites. This privacy statement applies solely to information collected by this Web site.

Surveys & Contests

From time-to-time our site requests information from users via surveys or contests. Participation in these surveys or contests is completely voluntary and the user therefore has a choice whether or not to disclose any information requested. Information requested may include contact information (such as name and delivery address), and demographic information (such as postcode, age level). Contact information will be used to notify the winners and award prizes. Survey information will be used for purposes of monitoring or improving the functionality of the site.


If a user elects to use our referral service for informing a friend about our site, we ask them for the friend’s name and email address. Mondaq stores this information and may contact the friend to invite them to register with Mondaq, but they will not be contacted more than once. The friend may contact Mondaq to request the removal of this information from our database.


This website takes every reasonable precaution to protect our users’ information. When users submit sensitive information via the website, your information is protected using firewalls and other security technology. If you have any questions about the security at our website, you can send an email to

Correcting/Updating Personal Information

If a user’s personally identifiable information changes (such as postcode), or if a user no longer desires our service, we will endeavour to provide a way to correct, update or remove that user’s personal data provided to us. This can usually be done at the “Your Profile” page or by sending an email to

Notification of Changes

If we decide to change our Terms & Conditions or Privacy Policy, we will post those changes on our site so our users are always aware of what information we collect, how we use it, and under what circumstances, if any, we disclose it. If at any point we decide to use personally identifiable information in a manner different from that stated at the time it was collected, we will notify users by way of an email. Users will have a choice as to whether or not we use their information in this different manner. We will use information in accordance with the privacy policy under which the information was collected.

How to contact Mondaq

You can contact us with comments or queries at

If for some reason you believe Mondaq Ltd. has not adhered to these principles, please notify us by e-mail at and we will use commercially reasonable efforts to determine and correct the problem promptly.