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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-03-12</periodOfReport>

    <issuer>
        <issuerCik>0001739104</issuerCik>
        <issuerName>Elanco Animal Health Inc</issuerName>
        <issuerTradingSymbol>ELAN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001752437</rptOwnerCik>
            <rptOwnerName>Cabral Ramiro Martin</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ELANCO ANIMAL HEALTH INCORPORATED</rptOwnerStreet1>
            <rptOwnerStreet2>2500 INNOVATION WAY</rptOwnerStreet2>
            <rptOwnerCity>GREENFIELD</rptOwnerCity>
            <rptOwnerState>IN</rptOwnerState>
            <rptOwnerZipCode>46140</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>See Remarks</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2019-03-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>20039</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>32780</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Grant of restricted stock units pursuant to the 2018 Elanco Stock Plan on March 12, 2019, with 8,836 vesting on December 31, 2019 and 11,203 vesting on December 31, 2020. Awards issued in replacement of previously held awards with respect to shares of common stock of Eli Lilly &amp; Company (Lilly), which were forfeited in connection with the completion of an exchange offer on March 11, 2019 by Lilly, in which Lilly disposed of all of Elanco's shares held by it.</footnote>
    </footnotes>

    <remarks>Executive Vice Presideent, Elanco International</remarks>

    <ownerSignature>
        <signatureName>/s/ Darlene Quashie Henry, as Attorney-in-Fact for Ramiro M. Cabral</signatureName>
        <signatureDate>2019-03-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
