-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 GsUnakIp6KNx5f/4AWEGDsTA7PuvbcVi/XNqogV7tixSmLeueawkv0n0za+Wqrv7
 TxKGoDpWI3OCulSl+NeZ5g==

<SEC-DOCUMENT>0001140361-10-037961.txt : 20100920
<SEC-HEADER>0001140361-10-037961.hdr.sgml : 20100919
<ACCEPTANCE-DATETIME>20100920144859
ACCESSION NUMBER:		0001140361-10-037961
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100916
FILED AS OF DATE:		20100920
DATE AS OF CHANGE:		20100920

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			RICHARDS JAMES C
		CENTRAL INDEX KEY:			0000942487

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-22872
		FILM NUMBER:		101080293

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SYMBOLLON CORP
		CENTRAL INDEX KEY:			0000912086
		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
		IRS NUMBER:				363463683
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		37 LORING DR
		CITY:			FRAMINGHAM
		STATE:			MA
		ZIP:			01702
		BUSINESS PHONE:		5084430165

	MAIL ADDRESS:	
		STREET 1:		37 LORING DRIVE
		CITY:			FRAMINGHAM
		STATE:			MA
		ZIP:			01702
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-09-16</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000912086</issuerCik>
        <issuerName>SYMBOLLON CORP</issuerName>
        <issuerTradingSymbol>SYMBA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000942487</rptOwnerCik>
            <rptOwnerName>RICHARDS JAMES C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SYMBOLLON PHARM.</rptOwnerStreet1>
            <rptOwnerStreet2>99 WEST STREET</rptOwnerStreet2>
            <rptOwnerCity>MEDFIELD</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02052</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-09-16</value>
                <footnoteId id="F1"/>
            </transactionDate>
            <deemedExecutionDate>
                <value>2010-09-16</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>500000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>.03</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>678701</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">250,000 shares vest each of the next two anniversaries.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>James C. Richards</signatureName>
        <signatureDate>2010-09-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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