<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType><periodOfReport>2003-08-05</periodOfReport>
    <issuer>
        <issuerCik>0000721371</issuerCik>
        <issuerName>CARDINAL HEALTH INC</issuerName>
        <issuerTradingSymbol>CAH</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001182939</rptOwnerCik>
            <rptOwnerName>MCCOY JOHN B</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>7000 CARDINAL PLACE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DUBLIN</rptOwnerCity>
            <rptOwnerState>OH</rptOwnerState>
            <rptOwnerZipCode>43017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
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son</value></natureOfOwnership></ownershipNature></nonDerivativeHolding><nonDerivativeTransaction><securityTitle><value>Common Shares</value></securityTitle><transactionDate><value>2003-08-05</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>203</value></transactionShares><transactionPricePerShare><value>56.50</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>2598</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>By Directors Deferred Compensation Plan</value></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeHolding><securityTitle><value>Common Shares</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>50773</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>By GRAT</value></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><derivativeTable><derivativeHolding><securityTitle><value>Option (right to buy)</value><footnoteId id="F1"/></securityTitle><conversionOrExercisePrice><value>13.553</value></conversionOrExercisePrice><exerciseDate><value>1994-11-08</value></exerciseDate><expirationDate><value>2004-11-08</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common 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Shares</value></underlyingSecurityTitle><underlyingSecurityShares><value>2138</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Option (right to buy)</value><footnoteId id="F2"/></securityTitle><conversionOrExercisePrice><value>33.28</value></conversionOrExercisePrice><exerciseDate><value>1997-11-05</value></exerciseDate><expirationDate><value>2007-11-05</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Shares</value></underlyingSecurityTitle><underlyingSecurityShares><value>3005</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Option (right to buy)</value><footnoteId id="F2"/></securityTitle><conversionOrExercisePrice><value>46.293</value></conversionOrExercisePrice><exerciseDate><value>1998-11-23</value></exerciseDate><expirationDate><value>2008-11-23</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Shares</value></underlyingSecurityTitle><underlyingSecurityShares><value>2160</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Option (right to buy)</value><footnoteId id="F2"/></securityTitle><conversionOrExercisePrice><value>29.958</value></conversionOrExercisePrice><exerciseDate><value>1999-11-03</value></exerciseDate><expirationDate><value>2009-11-03</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common 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Shares</value></underlyingSecurityTitle><underlyingSecurityShares><value>2064</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Option (right to buy)</value><footnoteId id="F3"/></securityTitle><conversionOrExercisePrice><value>62.50</value></conversionOrExercisePrice><exerciseDate><value>2000-11-01</value></exerciseDate><expirationDate><value>2010-11-01</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Shares</value></underlyingSecurityTitle><underlyingSecurityShares><value>1136</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Option (right to buy)</value><footnoteId id="F2"/></securityTitle><conversionOrExercisePrice><value>63.90</value></conversionOrExercisePrice><exerciseDate><value>2001-11-07</value></exerciseDate><expirationDate><value>2011-11-07</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Shares</value></underlyingSecurityTitle><underlyingSecurityShares><value>2019</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Option (right to buy)</value><footnoteId id="F3"/></securityTitle><conversionOrExercisePrice><value>63.90</value></conversionOrExercisePrice><exerciseDate><value>2001-11-07</value></exerciseDate><expirationDate><value>2011-11-07</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Shares</value></underlyingSecurityTitle><underlyingSecurityShares><value>1893</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Option (right to buy)</value><footnoteId id="F2"/></securityTitle><conversionOrExercisePrice><value>70.01</value></conversionOrExercisePrice><exerciseDate><value>2002-11-06</value></exerciseDate><expirationDate><value>2012-11-06</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Shares</value></underlyingSecurityTitle><underlyingSecurityShares><value>1843</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Option (right to buy)</value><footnoteId id="F3"/></securityTitle><conversionOrExercisePrice><value>70.01</value></conversionOrExercisePrice><exerciseDate><value>2002-11-06</value></exerciseDate><expirationDate><value>2012-11-06</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Shares</value></underlyingSecurityTitle><underlyingSecurityShares><value>1728</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding></derivativeTable><footnotes><footnote id="F1">Stock options granted pursuant to the Cardinal Health, Inc. Directors' Option Plan.</footnote><footnote id="F2">Stock options granted pursuant to the Cardinal Health, Inc. Equity Incentive Plan.</footnote><footnote id="F3">Stock options granted pursuant to the Cardinal Health, Inc. Outside Directors Equity Incentive Plan.</footnote></footnotes><remarks/><ownerSignature><signatureName>John B. McCoy</signatureName><signatureDate>2003-08-05</signatureDate></ownerSignature></ownershipDocument>

