Synthetic Biologics Reports Third Quarter 2014 Financial Results and Operational Highlights -- Company Completes $18.9 Million Net Registered Direct Offering; Finalizes Plans for Start of Clinical Trials in C. difficile

Synthetic Biologics Reports Third Quarter

2014 Financial Results and Operational Highlights

-- Company Completes $18.9 Million

Net Registered Direct Offering;

Finalizes Plans for Start of Clinical

Trials in C. difficile and C-IBS --

-- Conference Call Today, November

14, 2014, at 8:30 a.m. (EST); U.S. Participants Call (888) 347-5280 or

Join Webcast at http://www.videonewswire.com/event.asp?id=100975

MD, November 14, 2014 - Synthetic Biologics, Inc. (NYSE MKT: SYN), a developer

of pathogen-specific therapies for serious infections and diseases, with a focus on protecting the microbiome,

today reported financial results for the three and nine months ended September 30, 2014, and provided an operational update.

"We've made meaningful progress

with each of the programs in our pipeline, and we look forward to reporting the achievement of several milestones in the next six

months, including the C. difficile and C-IBS programs entering the clinic and the MS program completing ongoing MRI brain

scan analyses," said Jeffrey Riley, Chief Executive Officer of Synthetic Biologics. "With the completion of a capital

raise of $18.9 million in net proceeds with select institutional investors, we strengthened our cash position and added a new biotech

investor to our strong existing shareholder base. All of these efforts strengthen Synthetic Biologics' position for future

growth and success, which we believe significantly increases value for our shareholders."

Clinical Programs Update

Prevention of C. difficile (C. diff)

Infections - SYN-004 Oral Beta-Lactamase Enzyme

Relapsing-Remitting Multiple Sclerosis

(RRMS) - Trimesta (oral estriol)

Constipation-Predominant Irritable Bowel

Syndrome (C-IBS) - SYN-010 Statin-Class Oral Compound

Pertussis (Whooping Cough) - SYN-005

Monoclonal Antibody (mAb) Combination

Three and Nine Months Ended September

30, 2014 Financial Results

General and administrative expenses were

$1.2 million and $4.2 million for the three and nine months ended September 30, 2014, respectively, compared to $1.9 million and

$4.3 million for the same periods in 2013. These decreases of approximately 36% and 3%, respectively, are primarily the result

of bad debt expense of $763,000 associated with the note and interest receivables from the sale of Adeona Clinical Laboratory that

were determined uncollectible during the quarter ended September 30, 2013, which, for the nine months ended September 30, 2014,

was offset by supplemental compensation granted by the Board of Directors to executive officers and increased stock-based compensation

expense. Non-cash charges related to stock-based compensation were $377,000 and $1.3 million for the three and nine months ended

September 30, 2014, respectively, compared to $264,000 and $916,000 for the same periods in 2013.

Research and development expenses increased

to $3.7 million and $9.2 million for the three and nine months ended September 30, 2014, respectively, compared to $1.5 million

and $3.8 million, for the same periods in 2013. These increases of 150% and 144%, respectively, are primarily the result of increased

program costs associated with expanded research, clinical development and manufacturing activities within our pathogen-specific

pipeline, including the Company's C. difficile, C-IBS and Pertussis programs. Non-cash charges related to stock-based

compensation were $232,000 and $550,000 for the three and nine months ended September 30, 2014, respectively, compared to $74,000

and $286,000 for the same periods in 2013.

Other income was $1,000 and $97,000 for

the three and nine months ended September 30, 2014, respectively, compared to other expense of $3,000 and $27,000, for the same

September 30, 2014 was $3.3 million compared to $14.6 million at December 31, 2013. In addition, on October 16, 2014, Synthetic

Biologics closed a registered direct offering with select institutional investors for net proceeds of approximately $18.9

Synthetic Biologics will hold a conference

call today, Thursday, November 14, 2014, at 8:30 a.m. EST, during which Mr. Riley will provide an operational update and C. Evan

Ballantyne, Synthetic Biologics' Chief Financial Officer, will review the Company's financial results for the three and nine months

ended September 30, 2014.

Interested parties should call 1-888-347-5280

(U.S. toll free), 1-855-669-9657 (Canada toll free), or +1 412-902-4280 (International), fifteen minutes before the start of the

call to register. Registered callers on the toll free line may ask to be placed in the queue for the Question & Answer Session.

The call will also be webcast over the Internet at http://www.videonewswire.com/event.asp?id=100975. If you are unable to participate

during the live conference call, the webcast will be available for replay at the same URL, http://www.videonewswire.com/event.asp?id=100975,

for 30 days after the call.

About Synthetic Biologics, Inc.

Synthetic Biologics, Inc. (NYSE MKT: SYN)

is a clinical-stage biotechnology company developing pathogen-specific therapies for serious infections and diseases, with a focus

on protecting the microbiome. The Company is developing an oral biologic to protect the gastrointestinal (GI) microflora from the

effects of intravenous (IV) antibiotics for the prevention of C. difficile infection, an oral treatment to reduce the impact

of methane producing organisms on constipation-predominant irritable bowel syndrome (C-IBS) and a monoclonal antibody combination

for the treatment of Pertussis. In addition, the Company is developing a Phase 2 oral estriol drug for the treatment of relapsing-remitting

multiple sclerosis (MS) and cognitive dysfunction in MS. For more information, please visit Synthetic Biologics' website at www.syntheticbiologics.com.

This release includes forward-looking

statements on Synthetic Biologics' current expectations and projections about future events. In some cases forward-looking

statements can be identified by terminology such as "may," "should," "potential," "continue,"

"expects," "anticipates," "intends," "plans," "believes," "estimates,"

and similar expressions. These statements are based upon current beliefs, expectations and assumptions and are subject to a number

of risks and uncertainties, many of which are difficult to predict and include statements regarding advancing Synthetic Biologics'

clinical programs and achieving milestones, the ability to achieve future growth and success and increase shareholder value, and

the anticipated timing of the Synthetic Biologics' clinical trials, filing of INDs and release of results. The forward-looking

statements are subject to risks and uncertainties that could cause actual results to differ materially from those set forth or

implied by any forward-looking statements. Important factors that could cause actual results to differ materially from those reflected

in Synthetic Biologics' forward-looking statements include, among others, a failure to receive the necessary regulatory approvals

for commercialization of Synthetic Biologics' therapeutics, a failure of Synthetic Biologics' clinical trials, and

those conducted by investigators, to be commenced or completed on time or to achieve desired results, a failure of Synthetic Biologics'

clinical trials to receive anticipated funding, a failure of Synthetic Biologics' products for the prevention and treatment

of diseases to be successfully developed or commercialized, Synthetic Biologics' inability to maintain its licensing agreements,

or a failure by Synthetic Biologics or its strategic partners to successfully commercialize products and other factors described

in Synthetic Biologics' report on Form 10-K for the year ended December 31, 2013 and any other filings with the SEC. The

information in this release is provided only as of the date of this release, and Synthetic Biologics undertakes no obligation to

update any forward-looking statements contained in this release on account of new information, future events, or otherwise, except

For further information, please contact:

Synthetic Biologics: Kris Maly, VP, Corporate

Communication, (734) 332-7800, info@syntheticbiologics.com

Media: Wendy Emanuel, Wellspring Communications,

Inc., (773) 255-9580, wendy@wellspringcom.com

- Financial Tables Follow -

Synthetic Biologics, Inc. and Subsidiaries

(in thousands, except share and per share amounts)

Condensed Consolidated Balance Sheets

Condensed Consolidated Statements of Operations