BELLUS Health : Forms of Proxy

Security Class

Holder Account Number

Form of Proxy - Annual and Special Meeting to be held on June 30, 2023 at 11:30 am This Form of Proxy is solicited by and on behalf of Management.

Notes to proxy

1. Every holder has the right to appoint some other person or company of their choice, who need not be a holder, to attend and act on their behalf at the meeting or any adjournment or postponement thereof. If you wish to appoint a person or company other than the Management Nominees whose names are printed herein, please insert the name of your chosen proxyholder in the space provided (see reverse).
2. If the securities are registered in the name of more than one owner (for example, joint ownership, trustees, executors, etc.), then all those registered should sign this proxy. If you are voting on behalf of a corporation or another individual you may be required to provide documentation evidencing your power to sign this proxy with signing capacity stated.
3. This proxy should be signed in the exact manner as the name(s) appear(s) on the proxy.
4. If a date is not inserted in the space provided on the reverse of this proxy, it will be deemed to bear the date on which it was mailed to the holder by Management.
5. The securities represented by this proxy will be voted as directed by the holder, however, if such a direction is not made in respect of any matter, and the proxy appoints the Management Nominees listed on the reverse, this proxy will be voted as recommended by Management.
6. The securities represented by this proxy will be voted in favour, or withheld from voting, or voted against each of the matters described herein, as applicable, in accordance with the instructions of the holder, on any ballot that may be called for. If you have specified a choice with respect to any matter to be acted on, the securities will be voted accordingly.
7. This proxy confers discretionary authority in respect of amendments or variations to matters identified in the Notice of Meeting and accompanying management information circular of BELLUS Health Inc. dated May 31, 2023, or other matters that may properly come before the meeting or any adjournment or postponement thereof, unless prohibited by law.
8. This proxy should be read in conjunction with the accompanying documentation provided by Management.

Proxies submitted must be received by 11:30 am, Eastern Daylight Time, on June 28, 2023.

VOTE USING THE TELEPHONE OR INTERNET 24 HOURS A DAY 7 DAYS A WEEK!

To Vote Using the Telephone		To Vote Using the Internet
• Call the number listed BELOW from a touch tone	•	Go to the following web site:
telephone.		www.investorvote.com
1-866-732-VOTE (8683) Toll Free	•	Smartphone?
	Scan the QR code to vote now.

If you vote by telephone or the Internet, DO NOT mail back this proxy.

Voting by mail may be the only method for securities held in the name of a corporation or securities being voted on behalf of another individual.

Voting by mail or by Internet are the only methods by which a holder may appoint a person as proxyholder other than the Management Nominees named on the reverse of this proxy. Instead of mailing this proxy, you may choose one of the two voting methods outlined above to vote this proxy.

To vote by telephone or the Internet, you will need to provide your CONTROL NUMBER listed below.

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CONTROL NUMBER

Appointment of Proxyholder

I/We being holder(s) of securities of BELLUS Health Inc. (the	OR	Print the name of the person you are
"Company") hereby appoint: Dr. Francesco Bellini, O.C., or failing this	appointing if this person is someone
person, Mr. Roberto Bellini, or failing this person, Mr. Ramzi Benamar, or		other than the Management
failing this person, Mr. Sébastien Roy (the "Management Nominees")		Nominees listed herein.

as my/our proxyholder with full power of substitution and to attend, act and to vote for and on behalf of the holder in accordance with the following direction (or if no directions have been given, as the proxyholder sees fit) and on all other matters that may properly come before the Annual and Special Meeting of shareholders of the Company to be held at 275 Armand Frappier Blvd., Laval, Québec, H7V 4A7 on June 30, 2023 at 11:30 am, and at any adjournment or postponement thereof.

VOTING RECOMMENDATIONS ARE INDICATED BY HIGHLIGHTED TEXT OVER THE BOXES.

1. Election of Directors

1. Dr. Francesco Bellini, O.C.

1. Franklin M. Berger, CFA

1. Dr. William Mezzanotte

For

Against

02. Roberto Bellini

05. Dr. Clarissa Desjardins

08. Joseph Rus

For

Against

03. Dr. Youssef L. Bennani

06. Pierre Larochelle

For

Against

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For

Withhold

2. Appointment of Auditors

Appointment of KPMG LLP as Auditors of the Company for the ensuing year and authorizing the Audit Committee to fix their remuneration.

3. Resolution - Stock Option Plan

Ratification and confirmation of a resolution approving the unallocated options under the Stock Option Plan.

For

Against

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Signature of Proxyholder

Signature(s)

Date

I/We authorize you to act in accordance with my/our instructions set out above. I/We hereby revoke any proxy previously given with respect to the Meeting. If no voting instructions are indicated above, and the proxy appoints the Management Nominees, this Proxy will be voted as recommended by Management.

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