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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-12-30</periodOfReport>

    <issuer>
        <issuerCik>0001472595</issuerCik>
        <issuerName>Accretive Health, Inc.</issuerName>
        <issuerTradingSymbol>AH</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001492076</rptOwnerCik>
            <rptOwnerName>FW Oak Hill Accretive Healthcare Investors, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>201 MAIN STREET</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 3100</rptOwnerStreet2>
            <rptOwnerCity>FORT WORTH</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>76102</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001247520</rptOwnerCik>
            <rptOwnerName>GROUP VI 31 LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>201 MAIN STREET</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 3100</rptOwnerStreet2>
            <rptOwnerCity>FORT WORTH</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>76102</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000911380</rptOwnerCik>
            <rptOwnerName>CRANDALL J TAYLOR</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2775 SAND HILL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 220</rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-12-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3828</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>14850282</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Distribution of shares to limited partners for no consideration. The distribution was made for estate planning purposes.</footnote>
        <footnote id="F2">Group VI 31, LLC (&quot;Group VI 31&quot;) is the sole general partner of FW Oak Hill Accretive Healthcare Investors, L.P. (the &quot;Oak Hill Partnership&quot;), which is the direct holder of the shares reported herein.  J. Taylor Crandall (&quot;Crandall&quot;) is the sole member and President of Group VI 31 and a limited parter of the Oak Hill Partnership.  Crandall and Group VI 31 disclaim beneficial ownership of the reported securities except to the extent of their pecuniary interest therein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Kevin G. Levy, Vice President of Group VI 31, LLC, general partner of FW Oak Hill Accretive Healthcare Investors, L.P.</signatureName>
        <signatureDate>2011-01-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Kevin G. Levy, Vice President of Group VI 31, LLC</signatureName>
        <signatureDate>2011-01-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Kevin G. Levy, as Attorney-in-Fact for J. Taylor Crandall</signatureName>
        <signatureDate>2011-01-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
