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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-03-11</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>2019-03-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1227</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>12741</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On March 11, 2019, Eli Lilly and Company (&quot;Lilly&quot;) announced the completion of its offer to exchange shares of Lilly common stock for all of the common stock of the Issuer owned by Lilly (the &quot;Exchange Offer&quot;). The Reporting Person tendered 2,000 shares of Lilly common stock in the Exchange Offer, which shares were subject to a proration factor of 13.5970839%.  As a result, the Reporting Person received 1,227 shares of Issuer common stock in exchange for 272 shares of Lilly common stock accepted in the Exchange Offer, based on an exchange ratio of 4.5121 shares of Issuer common stock for each share of Lilly common stock accepted.</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>2019-03-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
