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                    <ccc>XXXXXXXX</ccc>
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            <liveTestFlag>LIVE</liveTestFlag>



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        <issuerInfo>
            <issuerCik>0001446847</issuerCik>
            <issuerName>IRONWOOD PHARMACEUTICALS INC.</issuerName>
            <secFileNumber>001-34620</secFileNumber>
            <issuerAddress>
                <ns2:street1>100 SUMMER STREET, SUITE 2300</ns2:street1>
                <ns2:city>BOSTON</ns2:city>
                <ns2:stateOrCountry>MA</ns2:stateOrCountry>
                <ns2:zipCode>02110</ns2:zipCode>
            </issuerAddress>
            <issuerContactPhone>(617) 621-7722</issuerContactPhone>
            <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>THOMAS MCCOURT</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
            <relationshipsToIssuer>
                <relationshipToIssuer>Officer</relationshipToIssuer>
                <relationshipToIssuer>Director</relationshipToIssuer>
            </relationshipsToIssuer>
        </issuerInfo>
        <securitiesInformation>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <brokerOrMarketmakerDetails>
                <name>Morgan Stanley Smith Barney LLC</name>
                <address>
                    <ns2:street1>1 New York Plaza</ns2:street1>
                    <ns2:street2>38th Floor</ns2:street2>
                    <ns2:city>New York</ns2:city>
                    <ns2:stateOrCountry>NY</ns2:stateOrCountry>
                    <ns2:zipCode>10004</ns2:zipCode>
                </address>
            </brokerOrMarketmakerDetails>
            <noOfUnitsSold>21148</noOfUnitsSold>
            <aggregateMarketValue>224653.09</aggregateMarketValue>
            <noOfUnitsOutstanding>155346103</noOfUnitsOutstanding>
            <approxSaleDate>05/08/2023</approxSaleDate>
            <securitiesExchangeName>NASD</securitiesExchangeName>
        </securitiesInformation>
        <securitiesToBeSold>
            <securitiesClassTitle>COMMON</securitiesClassTitle>
            <acquiredDate>02/23/2023</acquiredDate>
            <natureOfAcquisitionTransaction>Performance Shares</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>ISSUER</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>21148</amountOfSecuritiesAcquired>
            <paymentDate>02/23/2023</paymentDate>
            <natureOfPayment>NONE</natureOfPayment>
        </securitiesToBeSold>
        <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>THOMAS MCCOURT</name>
                <address>
                    <ns2:street1>100 SUMMER STREET, SUITE 2300</ns2:street1>
                    <ns2:city>BOSTON</ns2:city>
                    <ns2:stateOrCountry>MA</ns2:stateOrCountry>
                    <ns2:zipCode>02110</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>COMMON</securitiesClassTitle>
            <saleDate>03/27/2023</saleDate>
            <amountOfSecuritiesSold>46129</amountOfSecuritiesSold>
            <grossProceeds>492189.00</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>THOMAS MCCOURT</name>
                <address>
                    <ns2:street1>100 SUMMER STREET, SUITE 2300</ns2:street1>
                    <ns2:city>BOSTON</ns2:city>
                    <ns2:stateOrCountry>MA</ns2:stateOrCountry>
                    <ns2:zipCode>02110</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>COMMON</securitiesClassTitle>
            <saleDate>03/03/2023</saleDate>
            <amountOfSecuritiesSold>33756</amountOfSecuritiesSold>
            <grossProceeds>378833.00</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
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                <address>
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                    <ns2:city>BOSTON</ns2:city>
                    <ns2:stateOrCountry>MA</ns2:stateOrCountry>
                    <ns2:zipCode>02110</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>COMMON</securitiesClassTitle>
            <saleDate>02/28/2023</saleDate>
            <amountOfSecuritiesSold>61231</amountOfSecuritiesSold>
            <grossProceeds>695694.00</grossProceeds>
        </securitiesSoldInPast3Months>
        <noticeSignature>
            <noticeDate>05/08/2023</noticeDate>
            <planAdoptionDates>
                <planAdoptionDate>12/12/2022</planAdoptionDate>
            </planAdoptionDates>
            <signature>/s/ Thomas McCourt</signature>
        </noticeSignature>
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144
0001478448
XXXXXXXX
LIVE
0001446847
IRONWOOD PHARMACEUTICALS INC.
001-34620
100 SUMMER STREET, SUITE 2300
BOSTON
MA
02110
(617) 621-7722
THOMAS MCCOURT
Officer
Director
Common
Morgan Stanley Smith Barney LLC
1 New York Plaza
38th Floor
New York
NY
10004
21148
224653.09
155346103
05/08/2023
NASD
COMMON
02/23/2023
Performance Shares
ISSUER
N
21148
02/23/2023
NONE
N
THOMAS MCCOURT
100 SUMMER STREET, SUITE 2300
BOSTON
MA
02110
COMMON
03/27/2023
46129
492189.00
THOMAS MCCOURT
100 SUMMER STREET, SUITE 2300
BOSTON
MA
02110
COMMON
03/03/2023
33756
378833.00
THOMAS MCCOURT
100 SUMMER STREET, SUITE 2300
BOSTON
MA
02110
COMMON
02/28/2023
61231
695694.00
05/08/2023
12/12/2022
/s/ Thomas McCourt