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    <periodOfReport>2017-03-06</periodOfReport>

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    <issuer>
        <issuerCik>0001124804</issuerCik>
        <issuerName>ALLSCRIPTS HEALTHCARE SOLUTIONS, INC.</issuerName>
        <issuerTradingSymbol>MDRX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001511354</rptOwnerCik>
            <rptOwnerName>Black Paul</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 MERCHANDISE MART PLAZA</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 2024</rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60654</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

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                    <value>1395630</value>
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                    <value>D</value>
                </directOrIndirectOwnership>
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        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
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            <transactionDate>
                <value>2017-03-06</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
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                <transactionFormType>4</transactionFormType>
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                <value></value>
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                    <value>15857</value>
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                    <value>11.93</value>
                </transactionPricePerShare>
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                    <value>D</value>
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                    <value>1380773</value>
                    <footnoteId id="F4"/>
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    <footnotes>
        <footnote id="F1">Award of service-based Restricted Stock Units granted under the Allscripts Healthcare Solutions, Inc. 2011 Stock Incentive Plan on March 6, 2017(the &quot;Grant Date&quot;).  The award vests 33% per year on each of the first three anniversaries of the Grant Date, subject to achievement of a performance goal for the period ending December 31, 2017.</footnote>
        <footnote id="F2">Withholding shares solely to cover withholding tax liabilities in connection with the vesting of performance stock units on March 6, 2017.</footnote>
        <footnote id="F3">On February 25, 2014 (the &quot;Grant Date&quot;), the reporting person was granted performance-based restricted stock units (&quot;PSUs&quot;), the vesting of which was subject to both continued service and a performance measure of a combination of 50% non-GAAP adjusted EBITDA and 50% non-GAAP revenue targets being attained for successive one-year, two-year and three-year performance periods commencing on the Grant Date.  The acquisition of shares of the Issuer's common stock represents the vesting of PSUs for the three-year performance period ending three years from the Grant Date.</footnote>
        <footnote id="F4">The beneficial ownership number includes 1,000 shares obtainned through the reporting person's involvement in the Company's Employee Stock Purchase Plan.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Holly O'Berry by power of attorney for Paul Black</signatureName>
        <signatureDate>2017-03-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
