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

    <documentType>4/A</documentType><periodOfReport>2000-11-16</periodOfReport><dateOfOriginalSubmission>2000-12-08</dateOfOriginalSubmission>
    <issuer>
        <issuerCik>0000104207</issuerCik>
        <issuerName>WALGREEN CO</issuerName>
        <issuerTradingSymbol>WAG</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001197070</rptOwnerCik>
            <rptOwnerName>FERSTEL MARILOU VON</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>200 WILMOT ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DEERFIELD</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60015</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeHolding><securityTitle><value>Walgreen Co. Common Stock</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>100</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>See footnote</value><footnoteId id="F1"/></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><footnotes><footnote id="F1">Ms. von Ferstel is custodian under the Illinois Uniform Transfer to Minors Act.  This form is being amended solely to correct a clerical error in the number of shares reported.  </footnote></footnotes><remarks/><ownerSignature><signatureName>Sara K. Roach by power of attorney</signatureName><signatureDate>2003-11-03</signatureDate></ownerSignature></ownershipDocument>

