<SEC-DOCUMENT>0001209191-21-048660.txt : 20210729
<SEC-HEADER>0001209191-21-048660.hdr.sgml : 20210729
<ACCEPTANCE-DATETIME>20210729183519
ACCESSION NUMBER:		0001209191-21-048660
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210727
FILED AS OF DATE:		20210729
DATE AS OF CHANGE:		20210729

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Sims Andrew John Hugh MacIntyre
		CENTRAL INDEX KEY:			0001802687

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34375
		FILM NUMBER:		211129151

	MAIL ADDRESS:	
		STREET 1:		4200 MARATHON BOULEVARD
		STREET 2:		SUITE 200
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78756

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PLUS THERAPEUTICS, INC.
		CENTRAL INDEX KEY:			0001095981
		STANDARD INDUSTRIAL CLASSIFICATION:	SURGICAL & MEDICAL INSTRUMENTS & APPARATUS [3841]
		IRS NUMBER:				330827593
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		4200 MARATHON BLVD.
		STREET 2:		SUITE 200
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78756
		BUSINESS PHONE:		737.255.7194

	MAIL ADDRESS:	
		STREET 1:		4200 MARATHON BLVD.
		STREET 2:		SUITE 200
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78756

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	CYTORI THERAPEUTICS, INC.
		DATE OF NAME CHANGE:	20050712

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MACROPORE INC
		DATE OF NAME CHANGE:	20010320
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-07-27</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001095981</issuerCik>
        <issuerName>PLUS THERAPEUTICS, INC.</issuerName>
        <issuerTradingSymbol>PSTV</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001802687</rptOwnerCik>
            <rptOwnerName>Sims Andrew John Hugh MacIntyre</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PLUS THERAPEUTICS INC.</rptOwnerStreet1>
            <rptOwnerStreet2>4200 MARATHON BOULEVARD, SUITE 200</rptOwnerStreet2>
            <rptOwnerCity>AUSTIN</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>78756</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Financial Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-07-27</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1986</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>2.05</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1986</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-07-28</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2244</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.9099</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4230</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Andrew Sims</signatureName>
        <signatureDate>2021-07-29</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
