<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-04-30</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001308027</issuerCik>
        <issuerName>Vystar Corp</issuerName>
        <issuerTradingSymbol>vyst</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001473625</rptOwnerCik>
            <rptOwnerName>Allegra Joseph</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>VYSTAR CORPORATION, 3235 SATELLITE BLVD.</rptOwnerStreet1>
            <rptOwnerStreet2>BUILDING 400, SUITE 290</rptOwnerStreet2>
            <rptOwnerCity>DULUTH</rptOwnerCity>
            <rptOwnerState>GA</rptOwnerState>
            <rptOwnerZipCode>30096</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>common stock, par value $0.0001</value>
            </securityTitle>
            <transactionDate>
                <value>2010-04-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>30000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.25</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>355000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Diamond II Investments, LLC</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>warrants to purchase common stock, par value $0.0001</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1.5</value>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-04-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F3"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>15000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2010-04-30</value>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>common stock, par value $0.0001</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>15000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>545000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F5"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Diamond II Investments, LLC</value>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>warrants to purchase common stock, par value $0.0001</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>3.25</value>
                <footnoteId id="F6"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-04-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F3"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>15000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2010-04-30</value>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>common stock, par value $0.0001</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>15000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>560000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F7"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Diamond II Investments, LLC</value>
                    <footnoteId id="F7"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">115,000 shares are held by Dr. Allegra directly.  240,000 shares are held by Diamond II Investments, LLC.  Dr. Allegra is a Member and manager of Dianmond II Investments, LLC.</footnote>
        <footnote id="F2">Pursuant to the revision of the terms of the issuer's private placement, the exercise price of these warrants was reduced to $1.00 per share for the period from April 30, 2010 to June 28, 2010.  Thereafter, the exercise price reverts to $1.50 for the remainder of the term of the warrants.</footnote>
        <footnote id="F3">Pursuant to the revision of the terms of the issuer's private placement, which modified the purchase price of the issuer's common stock, additional warrants to purchase shares of common stock were issued to all prior purchasers including the reporting person.</footnote>
        <footnote id="F4">7,500 expire on December 22, 2010, and 7,500 expire on January 11, 2011.</footnote>
        <footnote id="F5">105,000 warrants and 400,000 options are held by Dr. Allegra directly.  40,000 warrants are held by Diamond II Investments, LLC.  Dr. Allegra is a Member and Manager of Diamond II Investments, LLC.</footnote>
        <footnote id="F6">Pursuant to the revision of the terms of the issuer's private placement, the exercise price of these warrants was reduced to $1.00 per share for the period from April 30, 2010 to June 28, 2010.  Thereafter, the exercise price reverts to $3.25 for the remainder of the term of the warrants.</footnote>
        <footnote id="F7">120,000 warrants and 400,000 options are held by Dr. Allegra directly.  40,000 warrants are held by Diamond II Investments, LLC.  Dr. Allegra is a Member and Manager of Diamond II Investments, LLC.</footnote>
    </footnotes>

    <remarks>Pursuant to the revision of the terms of the issuer's private placement, which modified the purchase price of the issuer's common stock, additional shares of common stock were issued to all prior purchasers including the reporting person.</remarks>

    <ownerSignature>
        <signatureName>gerald l baxter</signatureName>
        <signatureDate>2010-05-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
