Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2011	Mar. 26, 2012	Jun. 30, 2011
Entity Registrant Name	Synthetic Biologics, Inc.
Entity Central Index Key	0000894158
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Trading Symbol	syn
Entity Common Stock, Shares Outstanding		32,701,984
Document Type	10-K
Amendment Flag	true
Document Period End Date	Dec. 31, 2011
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2011
Entity Well-Known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 16,266,000
Amendment Description	On May 1, 2012, we were informed by Berman & Company, P.A. ("Berman & Company"), our independent registered accounting firm, that during a regular Public Company Accounting Oversight Board ("PCAOB") inspection of Berman & Company, the PCAOB issued a comment that the audit opinion included in our Annual Report on Form 10-K for the year ended December 31, 2011 was issued by a partner at Berman & Company who was not authorized under the PCAOB rules to issue the opinion or act as our named engagement partner with respect to the Form 10-K audit (or prior 2011 Form 10-Q interim reviews) after the original engagement partner rotated off the account under the Securities and Exchange Commission's independence rules as it pertains to partner rotation (S-X Rule 2-01 - Qualifications of Accountants). We believe that our previously filed financial statements for the year ended December 31, 2011 are accurate. In addition, we have not been informed by Berman & Company or the PCAOB, that our previously filed financial statements for the year ended December 31, 2011 are not accurate or otherwise invalid. As a matter of precaution the new engagement partner at Berman & Company has since: (i) taken full responsibility for the audit as the lead engagement partner on the audit, (ii) performed a detailed review of all audit procedures related to the original audit for sufficiency and (iii) reissued the audit opinion. We are filing this Annual Report on Form 10-K/A solely for the purpose of providing the reissued audit opinion and related disclosure, and subsequent event disclosure regarding the appointment of an independent, non-executive Chairman of the Board on May 10, 2012. The review performed by the new audit partner did not result in any changes to our financial statements or notes to the financial statements for the year ended December 31, 2011, other than the addition of the May 1, 2012 and May 10, 2012 disclosures in the subsequent event note to the financial statements.